Practice Sheet – SLM va1. A ball is thrown vertically upward from the

ground with a velocity of 30m/s. How long does it take to rise to its highest point

2. In the previous problem the maximum height attained by the particle

3. In the previous problem how long after projection will the ball have a velocity of 10m/s upward

4. In the previous problem how long after projection will the ball have a velocity of 10m/s downward

5. In the previous problem how long after the displacement of the ball will be zero

6. In the previous problem how long after projection will the ball have a velocity equal to half its velocity of projection

7. In the previous problem how long after projection will the ball have a displacement equal to half its maximum displacement

8. The velocity of a particle is given by v = 5 –t2 m/s. The average acceleration of the particle between 3 and 5 seconds will be.-[1] 2 m/s2

[2] –8 m/s2

[3] –14 m/s[4] 9 m/s2

9. A body of mass 4 kg has an initial velocity of î

m/s. It is subjected to a force of 4 j N. The distance of the body from origin after 4s will be.-[1] 25 m[2] 20 m[3] 21.5 m[4] 26.2 m

10.If the velocity of a particle is given by v = (180-6x)1/2 m/s, its acceleration will be[1] -3m/s2

[2] 6m/s2

[3] -6m/s2

[4] Cannot be determined from this equation

11.The velocity of a particle is zero at t=0. Which of the following is not correct for the particle?[1] The acceleration at t=0 must be zero[2] The acceleration at t=0 may be zero[3] If the acceleration is zero from t=0 to t=10sec, the speed is also zero in this interval[4] If the speed is zero from t=0 to t=10sec, the acceleration is also zero in this interval

12.A, B, C & D are points in a vertical line such that AB = BC = CD. If a body falls from rest at A, then the time intervals of descent through AB, BC & CD are in the ratio[1] 1: 4: 9

[2] 1: 1: 1 [3] 1: 3: 5 [4] 1: (2-1): (3-2)s

13.A body is dropped from a height h & a second body is thrown vertically up with a speed (gh)1/2. They meet at a height [1] h/2m from the ground [2] h/4m from the ground [3] 3h/4m from the ground [4] They will never meet

14.A body dropped from a height h at t-0 reaches the ground at t = t0. It would have reached a height h/ 2 at t [1] to2 [2] to/2 [3] to/2 [4] to/4

15.If the velocity of car is increased by 20% the minimum distance in which it can be stopped increases by[1] 40% [2] 44% [3] 68% [4] 80%

16.A particle moves along the x-axis according to the following equation : x=50t+10t2 where x is in m & t is in seconds. The average velocity of the particle during the first 3.0sec of its motion.[1] 80m/s [2] 240m/s [3] 120m/s [4] 20m/s

17.In the previous question, the instantaneous velocity of the particle at t=3.0sec[1] 110m/s [2] 240m/s [3] 120m/s [4] 20m/s

18.In the previous que., the acceleration at t =3.0sec[1] 110m/s2 [2] 240m/s2 [3] 20m/s2 [4] 0

19.An object falls from a bridge that is 45m above the water. It falls directly into a small boat moving with constant velocity that was 12m from the point of impact when the object was released. The speed of boat was[1] 4m/s

[2] 12m/s [3] 3m/s [4] 6m/s

20.A body moving with constant acceleration covers the distance between two points two points 60m apart in 6sec.Its velocity as it passes the second point is 15m/s.The acceleration of the particle is[1] 5/3m/s2

[2] 10/3m/s2

[3] 10m/s2

[4] 5m/s2

21.In the previous question, the velocity at the first point[1] 5m/s [2] 10m/s [3] 0 [4] 10m/s

22.The acceleration of the particle is given by a =2t2.If it is at rest at the origin at t =0, its position at t=1s will be[1] 1/6m [2] 1/3m [3] 2/3m [4] None of these

23.In the previous question the velocity at t=1sec[1] 2/3 m/s [2] 4/3 m/s [3] 1m/s [4] None of these

24.In the previous que., The acceleration at t=1sec[1] 2m/s2 [2] 4m/s2 [3] 1m/s2 [4] None of these

25.A body falls from rest was observed to fall through 78.4m in 2 sec. For how long had it been falling before it was observed [1] 4sec [2] 1sec [3] 2sec [4] 3sec

26.A solid ball of density half that of water falls under gravity from a height of 19.6m & then enters water. Up to what depth will it go? (neglect viscosity)[1] 19.6m [2] 9.8m [4] 4.9m (d) 39.6m

27.In the previous que, how much time will it take to come again to the water surface[1] 2s [2] 4s [3] 1s [4] It will never return

28.A particle is moving with constant acceleration the average velocity of the particle in the tth sec of its motion [1] ut + [a/2] t [2] u + [a/2] t [3] u + [a/2][2t-1][4] None

29.Wind is blowing west to east along the parallel tracks at a speed v. Two trains moving with the same speed in opposite direction have the steam track of one double that of the other. What is the speed of the train?[1] 2v [2] v [3] 3v [4] 4v

30.Two towers AB (20m high) & CD (30m high) are situated a distance d apart. An object of mass m is thrown from the top of AB along the horizontal with a velocity 10m/s towards CD. Simultaneously, another object of mass 2m is thrown from the top of CD at an angle of 600 with the horizontal downwards towards AB with the same magnitude of initial velocity as that of the first object. The two objects move in the same vertical plane, collide in mid air. The time after which they collide is [1] 2/3 sec [2] 10sec [3] 3/2 sec [4] 2sec

31.In the previous question, find the distance between the towers[1] 17m [2] 20/3m [3] 10/3m [4] 27m

32.A man standing on the edge of the terrace of a high rise building throws a stone, vertically up with a speed of 20m/s. Two seconds later, an identical stone is thrown vertically downwards with the same speed 20m/s.Then [1] The relative velocity between the stones remains constant till one hits the ground

[2] The time interval between their hitting is 2 sec[3] Both will have the same kinetic energy, when they hit the ground [4] All of the above are correct

33.A particle A is thrown in a vertically downwards with 10m/s another stone B is dropped from another tower at the same instant .It was found that both strikes the ground after 5sec the difference in the heights of the two tower is[1] Zero [2] 50m [3] 125m [4] Cannot be determined

34.In the previous problem the ratio of increase in velocity of A to B is [1] 6: 5 [2] 5: 6 [3] 1: 5 [4] 1: 1

35.A particle is dropped from a tower it strikes the ground with 8km/s. A stone thrown with 6km/s in a vertically upward direction will strike the ground with[1] 2km/s [2] 10km/s [3] 14km/s [4] 6km/s

36.If in the previous problem the second stone is thrown in a vertically downward direction with 6km/s then it will strike the ground with[1] 2km/s [2] 10km/s [3] 14km/s [4] 6km/s

37.A stone is thrown in a vertically upward direction from the top of a tower. It was found that the speed of the stone at a height ‘h’ below the point of projection is twice the speed at a height h above the point of projection. The maximum height attained by the particle [1] 10h/3 [2] 5h/3 [3] h/3 [4] None of these |

38.A particle has initial velocity of { i + j }

m/sand an acceleration of { i + j } m/s2 . Its speed after 10s will be.[1] 11 m/s[2] 22 m/s[3] 2 11 m/s[4] 11 2m/s

39.A body starts with an initial velocity of 10m/s & moves along a straight line with a constant acceleration. When the velocity of the particle is 50m/s the acceleration is reversed in direction. The velocity of the particle when it reaches the starting point is [1] 10m/s [2] 40m/s[3] 70m/s [4] The particle never reaches the starting point

40.A javelin is thrown at an angle with the horizontal & the maxi mum height attained by it is h. The time taken to attain this height is [1] h2sin2/g[2] (hsin/g)1/2

[3] (2h/g)1/2

[4] 2h/g

41.An elevator without a ceiling is ascending with a constant speed of 10m/s. A boy on the elevator

throws a ball directly upward, from a height of 2.0m above the elevator floor, with a velocity 20m/s relative to the elevator. The elevator floor at this instant is 28m above the ground. The maximum height attained by the ball is[1] 5m [2] 45m [3] 35m [4] 75m

42.In the previous question, how long does it take for ball to return to the elevator back to boy’s hand[1] 2sec [2] 4sec [3] 1sec [4] Cannot be determined

43.A ball is projected in a vertically downward direction with a velocity of 10m/s. The ratio of the distances traveled in the 1st, 2nd & 3rd sec of its motion.[1] 1: 3: 5 [2] 1: 4: 9 [3] 3: 5: 7 [4] None

44.A particle is projected vertically upwards from a point A on the ground .It takes t1sec to reach the ground a point B at a vertical height h from A but still continues to move upwards. If it further takes t2sec to reach the ground, then[1] h=[1/2] gt1t2

[2] h=[1/8]g[t1+t2]2

[3] h=[1/2]g[t1+t2]2 [4] h=[1/2]gt1

2

45.In the previous problem the maximum height attained [1] H =[1/2]gt1t2

[2] H =[1/8]g[t1+t2]2

[3] H =[1/2]g[t1+t2]2 [4] H =[1/2]gt1

2

46.In the previous problem the initial velocity is[1] [1/2]g(t1t2)

[2] [1/8]g(t1+t2)

[3] [1/2]g(t1+t2)

[4] [1/8]g(t1t2)47.An object is thrown vertically upwards. It has a

speed of 10m/s.when it as reached one half its maximum height. The maximum height attained by the particle[1] 20m [2] 10m [3] 5m [4] 15m

48.In the previous question the velocity 1 sec after it is thrown [1] 10m/s [2] 14.14m/s [3] 4.14m/s [4] Cannot be determined

49.In the previous question the acceleration 1 sec after it is thrown [1] 24.5m/s [2] 14.7m/s [3] 4.9m/s [4] 9.8m/s

50.A ball dropped from the top of a building takes 0.25sec to pass a window 3m high. How far is the top of the window from the top of the building?[1] 0.3m [2] 8.5m [3] 5.8m [4] Data is insufficient

51.A stone is dropped from the top of a tall cliff, & 1sec later a second stone is thrown vertically downward with a velocity of 20m/s. How far below the top of the cliff the second stone overtakes the first?[1] 5m [2] 11.2m [3] 1.25m [4] Data is insufficient

52.A ball is thrown vertically upwards from the ground & a student gazing out of the window sees it moving upwards past him at 5m/s. The window is 10m above the ground. How high does the ball goes above the ground?[1] 10.25m [2] 11.25m [3] 21.3m [4] 111m

53.In the previous que. , How long does it take to go from a height of 10m to its highest point.[1] 1s [2] 2.5s [3] 1.5s [4] 0.5sec

54.In the previous que, the velocity & acceleration after ½ sec it left the ground[1] 4.9m/s & -4.9m/s2 [2] 4.9m/s & -9.8m/s2

[3] 4.9m/s & -4.9m/s2

[4] 9.8m/s & -9.8m/s2

55.A stone is dropped from the top of a tower. If it travels 44.1m in the last second, The height of the tower must be[1] 240.1m [2] 122.5m [3] 176.4m [4] Cannot be determined

56.A body moving with a uniform acceleration describes 12m in the third sec of its motion & 20m in the fifth second. Its velocity after 10sec[1] 24m/s [2] 21m/s [3] 42m/s [4] Cannot be determined

57.A particle starts with uniform acceleration & its velocity after n sec is v. The displacement of the body in the last two sec is

[1]

2v (n−1 )n [2]

v (n−1 )n

[3]

v (n+1 )n [4]

2v (2n+1 )n

58.Two identical blocks A & B starts from rest from the top of inclined planes having the same vertical heights but inclined at 30o & 60o respectively. If va & vb represents the speed of the blocks at the bottom of the inclined [1] va > vb

[2] va < vb

[3] va = vb

[4] Cannot be said59.A particle is projected vertically upwards .The

time intervals from the start after which the particle is at ¾ of its maximum height are in the ratio[1] 1: 2 [2] 1: 3[3] 3: 1[4] The particle never reaches the same height twice

60.A ball is dropped from a height. If it takes 0.200sec to cross the last 6.00m before hitting the ground, find the height from where it was dropped [g=10m/s2][1] 12m [2] 24m [3] 48m [4] Cannot be determined

61.A man in a balloon rising vertically with an acceleration of 4.9 m/s2 releases a ball 2sec after the balloon has left the ground. The greatest height above the ground reached by the ball is [1] 14.7m [2] 19.6m [3] 9.8m [4] 24.5m

62.The acceleration of a particle is given by a=2t. If its velocity at t=1sec is 5m/s.its velocity at t=2sec is [1] 9m/s [2] 4m/s [3] 8m/s [4] 6m/s

63.In the previous problem the position of the particle at t=1sec is 6m,what is its position at t=2sec[1] 0.89 m [2] 12.33 m [3] 2.67m [4] None

64.The position of a particle is given by x =A sint where A & are constants. The velocity of the particle as a function of time [1] v =A sin t[2] v =A cos t [3] v =-A sin t[4] v =-A cos t

65.In the previous problem the acceleration of the particle as a function of time [1] a =-A2cost [2] a =-A2sint [3] a =A2cost [4] a =Asint

66.Consider the motion of the tip of the minute hand of a clock. In one hour[1] The displacement is zero [2] The distance covered is zero[3] The average speed is zero[4] None

67.A particle moves along the X-axis as x=u(t-2s)+a(t-2s)2

[1] The initial velocity of the particle is u [2] The acceleration of the particle is 2a [3] At t=2s particle is at the origin

[4] Both c & b

68.Which of the following(s) is correct[1] Average speed of a particle in a given time is never less than the magnitude of the average velocity[2] It is possible to have a situation in which dv /dt 0 but dv /dt=0[3] The average velocity of a particle is zero in a timeinterval. It is possible that the instantaneous velocity is never zero in the interval [4] The average velocity of a particle on a straight line is zero in a time interval. It is possible that the instantaneous velocity is never zero in the interval

69.An object may have [more than one ans. may be correct][1] Varying speed without having varying velocity[2] Varying velocity without having varying speed [3] Nonzero acceleration without having varying velocity[4] Nonzero acceleration without having varying speed

70.Mark the correct statement(s): [1] If the velocity & acceleration have opposite sign, the object is slowing down [2] If the velocity & position have opposite sign, the object is moving towards the origin [3] If the velocity is zero at an instant, the acceleration should be zero at that instant

[4] If the velocity is zero for a time interval, the acceleration is zero at any instant within the time interval

71.Mark the correct statement(s): [1] The magnitude of the velocity of a particle is equal to its speed[2] The magnitude of average velocity in an interval is equal to its average speed in that interval[3] It is possible to have a situation in which the speed of a particle is always zero but the average speed is not zero [4] None

72.A particle has a velocity u towards east at t=0.Its acceleration is towards west & is constant. Let xa & xb be its displacements in the first 10sec & the next 10sec

[1] xa xb

[2] xa xb [3] xa = xb [4] The information is not sufficient to find relation between xa with xb

73.A particle is thrown in a vertically upward direction with 39.2m/s the distance traveled in the last sec of its upward motion [1] 19.6m [2] 4.9m [3] 9.8m [4] one

74.If in the previous que., the velocity of the particle is 53m/s then the distance traveled in the last sec of its motion [1] 19.6m [2] 4.9m [3] 9.8m [4] None

75.A body is dropped from the top of a tower of height h & at the same instant, a body is projected from the foot of the same tower along the same vertical line with a velocity which would be just sufficient to take it to take it to the same height as that of tower. They will meet at a height [1] h/4m from the ground [2] h/2m from the ground[3] 3h/4m from the ground [4] 9h/16m from the ground

76.In the previous que, the time after which the balls collide is

[1] √ 2hg [2] √ hg

[3] √ h2 g [4]

2√ hg77.A particle starts from rest & moves with a

constant acceleration & attains a maximum velocity u & then undergoes a constant

retardation & comes to rest the average velocity of the particle during the motion [1] 2u [2] u/2 [3] u [4] Cannot be determined as the relation between acceleration & retardation is not given

78.A particle is thrown in a vertically upward direction at t=0, If the particle attains maximum height h at t=t0sec, where is the particle at t =3t0/2[1] h/4m from the ground [2] 3h/4m from the ground [3] 5h/4 m from the ground [4] h/2m from the ground

79.A particle is thrown in a vertically upward direction. It attains the maximum height after 4 sec. The ratio of distance traveled in the 1st,2nd,3rd & 4th sec of its motion[1] 1: 4: 9: 16 [2] 1: 3: 5: 7 [3] 7: 5: 3: 1 [4] 16: 9: 4: 1

80.In the previous que the ratio of distance traveled in the 4th , 5th, 6th & 7th sec of motion [1] 1: 4: 9: 16 [2] 1: 3: 5: 7 [3] 7: 5: 3: 1 [4] 1: 1: 3: 5

81.A ball is dropped from the top of the tower of height h. It covers a distance of h/2 in the last sec of its motion. How long does the ball remain in air?[g=10m/s2][1] 2sec [2] 2+2 sec [3] 2sec [4] None of the above

82.A car starts from rest & moves with constant acceleration. The ratio of the distance covered in the nth sec to that covered in n seconds

[1]

2n− 1

n2 [2]

2

n2−1n

[3]

1

n2−1n

[4]

1

n2−2n

83.If the acceleration of a particle is decreasing with time its velocity[1] Must be decreasing with time [2] Must be increasing with time [3] May increase with time [4] Cannot be said

84.A bus starts moving with acceleration 2m/s2. A cyclist 96m behind the bus starts simultaneous

towards the bus at 20m/s. After what time will he be able to overtake the first[1] 4sec [2] 8sec [3] 12sec [4] 16sec

85.In the above que., after some time the bus will be left behind. If the bus continues moving with the same acceleration, after what time from the beginning, the bus will overtake the cyclist[1] 10sec [2] 12sec [3] 14sec [4] 16sec

86.A body is projected vertically upwards. If t1 & t2 be the times at which it is at a height h above the point of projection while ascending & descending respectively, then h is[1] 1/2 g t1t2

[2] g t1t2 [3] 2g t1t2 [4] 4g t1t2

87.In the previous problem, the velocity of projection is [1] 1/2 g [t1+t2] [2] g [t1+t2] [3] 2g [t1+t2] [4] 4 g [t1+t2]

88.A stone thrown vertically upwards from the top of a tower with an initial velocity u, reaches the ground with a velocity 3u.The height of the tower is [1] 3u2/g [2] 4u2/g [3] 6u2/g [4] 9u2/g

89.A body of mass 2 kg crosses a point P with a velocity 80 m/s .A force of 20N directed towards P begins to act on it. It will again cross P in.-[1] 16s[2] 8s[3] 12s[4] 4s

90.A stone is dropped from the top of a 30m high cliff. At the same instant, another stone is projected vertically upwards from the ground with a speed of 30m/s. The two stones will cross each other after a time [1] 1sec [2] 2sec [3] 3sec [4] 4sec

91.In the previous que, The height at which the stones cross each other[1] 15m [2] 20m [3] 25m [4] 35m

92.Starting from rest & moving with a constant acceleration, a body covers a certain distance in time t. It covers the second half of distance in time

[1]

t2 [2] t [1+

1

√2 ]

[3] t [1-

1

√2 ] [4]

t

√2

93.The displacement of a particle moving in one dimension under the action of a constant force is related to the time t by the equation t=x+3 where x is in m & time is in sec., Find the displacement of the particle when the velocity is zero [1] 6m [2] 0 [3] 3m [4] 12m

94.A ball is thrown from the top of a tower in a vertically upward direction it takes t1 sec to reach the ground another ball thrown from the same point with the same speed but in a vertically downward direction takes time t2 to reach the ground. A stone dropped from the same tower takes t sec to reach the ground then

[1] t=√ t1 t2 [2] t= t1+ t2

[3] t=t1 t2 [4] t=(t1+ t2 )2

95.A rocket is fired vertically upwards & ascends with a constant vertical acceleration of 20ms-2 for 1.0 min. Its fuel is then all used. The maximum altitude reached[1] 72Km [2] 3.6Km [3] 108Km [4] 75.6Km

96.In the previous question the total time elapsed from takeoff until the rocket strikes the earth[1] 2min [2] 7min [3] 6min. [4] None of these

97.A ball is dropped from the top of a building .The ball takes 0.5sec to fall past the 3.0m length of a window some distance from the top of the building. The speed of the ball as it passed the top of the window[1] 7m/s [2] 35m/s [3] 8.5m/s [4] 3.5m/s

98.In the previous situation the height of the top of the window from the point where the ball was

dropped [1] 0.3m [2] 0.5m [3] 0.61m[4] Cannot be determined

99.A stone is thrown vertically upward. On its way up it passes a point A with speed v,& point B,3.00m higher than A, with speed v/2 .The speed v is [1] 3m/s [2] 5.4m/s [3] 8.9m/s [4] Cannot be determined

100. In the previous situation the maximum height reached by the stone above point B is[1] 2.0m [2] 1.0m [3] 3.0m [4] 4.0m

101. Two balls A & B ball are thrown in vertically upward & downward direction respectively, with a velocity of 20m/s from the top of a tower having a height of 50m.On its return A just misses the tower & finally strikes the ground. The difference in time intervals between the striking of the balls is [1] 2sec [2] 4sec [3] 8sec [4] There is no time difference

102. A stone is dropped from the top of a tower of height h. after 1 sec another stone is dropped from the balcony 20m below the top. Both strike the ground at the same instant. Then h is [1] 3125m [2] 312.5m [3] 31.25m [4] 25.31m

103. In the previous situation The time interval t1 elapsed [for the ball A] from the instant it was thrown until it passes the edge of the tower [1] 2sec [2] 4sec [3] 8sec [4] 1sec

104. In the previous situation, What velocity A has in this situation?[1] 10m/s downward [2] 20m/s upward [3] 20m/s downward [4] 37.4m/s downwards

105. In the previous situation the time t2 required for the ball A to reach the ground[1] 15sec [2] 4sec [3] 10sec[4] 5.7sec

106. In the previous problem the velocity with which the ball strikes the ground

[1] 10m/s downward [2] 20m/s upward [3] 20m/s downward [4] 37.4m/s downwards

107. Two blocks A & B are released simultaneously from the top of two smooth inclines having the same vertical height inclined at 30o & 60o respectively. If ta & tb represents the times of descent for A & B respectively then ta :tb

[1] 1:1 [2] 1: 3 [3] 3:1 [4] 1:2

108. A particle starts moving along a straight- line path with a velocity 10m/s. After 5sec,the distance of the particle from the starting point is 50m. Which of the following statements about the nature of the motion of the particle are correcti. The motion may be with constant accelerationii. The motion may be constant velocityiii. The motion is continuously retardediv. The motion may be first accelerated & then retarded[1] i & ii [2] i i & iv [3] i & ii [4] iii & iv

109. The distance traveled by a particle is directly proportional to t1/2 what is the nature of motion [1] Increasing acceleration [2] Decreasing acceleration [3] Increasing retardation [4] Decreasing retardation

110. A body dropped from the top of the tower covers a distance 7x in the last sec of its motion , where x is the distance traveled in the first sec of its motion the total time taken to reach the ground from the point it was dropped[1] 3sec [2] 4sec [3] 5sec [4] 6sec

111. A block released from an incline making an angle with the horizontal takes time t1 to reach the bottom & t2 when the same incline makes an angle with the horizontal .t1/t2 [1] sin /sin [2] ( sin /sin)1/2 [3] (sin/ sin )1/2 [4] 1:1

112. In the previous problem the ratio of speeds[1] sin /sin [2] ( sin /sin)1/2 [3] (sin/ sin )1/2 [4] 1:1

113. A driver of a car moving with a velocity v1 finds another car moving with velocity v2 [v1>v2]

the same direction along the same straight line. He applies the brakes & produces a retardation a, the minimum time required to avoid collision[1] (v1+v2)/a [2] (v1-v2)/a [3] (v2-v1)/a [4] a/ (v1-v2)

114. A particle, dropped from a height h, travels a distance 9h/25 in the last sec of its motion. If g=10m/s2

[1] 100m [2] 122.5m [3] 145m [4] 167.5mA

115. A man in a balloon rising vertically with an acceleration of 4.9 m/s2 releases a ball 2sec after the balloon has left the ground. The greatest height above the ground reached by the ball is [1] 14.7m [2] 19.6m [3] 9.8m [4] 24.5m

116. In the previous situation the time taken by the ball to reach the ground [1] 1sec [2] 2sec [3] 13 [4] 3

117. A point moves rectilinearly. Its displacement x at time t is given by x2 =t2+1. Its acceleration at time t is[1] 1/x [2] (1/x) –(1/x2)[3] –t/x2

[4] –t2/x3

[5] 1/x3

118. The instantaneous velocity of particle at an instant is equal to the time derivative of its position vector and the instantaneous acceleration is equal to the time derivative of its velocity vector. Therefore:[1] the instantaneous velocity depends on the instantaneous position vector[2] instantaneous acceleration is independent of instantaneous position vector and instantaneous velocity[3] instantaneous acceleration is independent of instantaneous position vector but depends upon instantaneous velocity[4] instantaneous acceleration depends on both instantaneous position vector and instantaneous velocity

119. The velocity of a particle is given by v = 5 –t2 m/s. The average acceleration of the particle between 3 and 5 seconds will be.-[a] 2 m/s2

[b] –8 m/s2

[c] –14 m/s[d] 9 m/s

120. A boy is let fall from a height of 120m. After 2 s of fall, if the gravity disappears, the total time taken to reach the ground is.[a] 3 s[b] 9 s[c] 5 s[d] 7 s