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1. What two measurements are needed to calculate the average speed of an object?
Distance and Time
answer
2. What equation would be used to calculate average speed?
Speed = distance / time
answer
3. A trolley takes 1.5 s to travel 60cm
Calculate its average speed..
v = d/t
= 60 / 1.5
= 40 cm/s
answer
4. Does a car speedometer give average or instantaneous speed?
instantaneous
answer
5. Give one advantage of using an electronic timer rather than a hand
held stopwatch.
Removes effect of reaction time
answer
6. What is meant by the term acceleration?
Change in speed per second
answer
7. Acceleration is measured in metres per second per second.
Write this in symbol form.
m/s/s or m/s2or ms-2
answer
8. What equation is used to find acceleration?
a = (v-u)/t
answer
9. An object starts from rest and reaches 8m/s after 4s .Find the acceleration.
a = (v-u) / t
= (8-0)/4
2 m/s2
answer
10. The times for 4 cars to reach 100 km/h are shown below. Which car has the greatest acceleration?
answer
Car Time(s)
A 10.1
B 8.3
C 16.4
D 12.9
Car B
(shortest time to go
from 0 – 100 km/h)
11. Describe the motion of the object represented by the speed – time graph
below.
Constant Speed answer
time
Speed
o
12. The velocity – time graphs for two objects are shown below
Which object has the larger acceleration.
Object A – steepest slope
answer
A
B
time
speed
O
13. What is represented by the area under a speed- time graph?
Distance travelled
answer
14. State three effects of a force.
Change of speed, shape and direction.
answer
15. What is the unit of Force?
Newtons (N)
answer
16. Name an instrument which can be used to measure forces.
Newton balance or spring balance.
answer
17. What is a Scalar Quantity? Give examples.
Scalar quantities can be described completely by their size or magnitude.
e.g. Distance, time, mass and speed
answer
18. What is a vector? Give examples.
Vectors are quantities with a magnitude and a direction. e.g. Weight, displacement, acceleration and velocity.
answer
19. What is the difference between speed and velocity.
Velocity = displacement/time
(vector)
Speed = distance / time
(scalar)
answer
20. Which force always opposes the motion of an object?
Friction
answer
21.The forces on the object below are balanced.
answer
50N
F50N
22. The forces on an object are balanced.Describe the possible motion of the
object.
answer
Stays at rest or moves with constant speed in a straight line.
23. An unbalanced force causes an object to accelerate.
What will affect the size of the acceleration?
answer
The size of the unbalanced force and the mass of the object
24. A dog runs 300m south then turns and runs a further 400m east in a total
time of 50s. What is the dog’s displacement from its starting position and
its average velocity?.answer
300m400m
300m
400mThis is the resultant displacement, the magnitude can be calculated by Pythagoras.
S = √(3002 + 4002)
S = 500m
We use SOH CAH TOA to work out angle x° which we need to give the direction.
tan X = 400/300 x° = tan-1 (400/300) x° = 53.1°
25. A 4kg object has an acceleration of 5m/s2.Find the unbalanced force acting on the object.
answer
F = m x a
= 4 x 5
= 20N
26. Find the acceleration of the object shown below.
answer
2m/s2
10kg20N