Physics Lesson No. 4S.Q. 4.1In case of person, d= 0 Another says P.E = mg (h1 + h2)

w= f (0) (His reference is Flour)= 0 S.Q. 4.7

In case of car, d= 0 The temperature of nose conew= f (0) become rise due to air friction or fluidw= 0 friction due to which it become hot.

In both cases d= 0 S.Q. 4.9w= 0 When cup is dropped, it have

S.Q. 4.2 P.E at certain height. If it move towordw = (KJ)? Earth, P.E → K.E. After strikingm = 10 kg P.E → Sound + heat energyh = 10 m P.E = k.E + Sound Energy + Heat Energy +g = 9.8 ms-2 Vibration K.Ew = mgh S.Q. 4.10 = 10 x 98/10 x 10 In the hand of boy, catapult have elastic = 980 J P.E. If stone is moved away from it,w = 0.98 KJ P.E → K.E. After smashes window, t, changeS.Q. 4.3 into a sound and heat energy.If force F, then distance L. Elastic P.E → K.E + Sound + Heat EnergyIf force is increased to 3 F,Then distance 2L.W1 = F x L = FLW2 = (3F) (2L) = 6FLWT = W1 + W2 = FL + 6FL = 7 FLS.Q. 4.4m = 50 KG m = 50 KGh = 50 cm d = 2 m = 50/100 F = 50 N = 0.5 m W2 = ?W1 = ? W2 = FDW1 = mgh = 50 x 2 = 50 x 9.8 x 0.5 = 100 Joule = 245 Joule

W1 > W2

S.Q. 4.5Given that P.E = 1 JouleP.E = mgh since w = mg = w.h = (1N) (1m)One Newton force is required to left the body atOne meter height to the One Joule work.S.Q. 4.6P.E = mghP.E = mg (h1 + h2)Both are correct.Reason:-

The students says P.E = mgh (His reference is Table)