Kevin Nash
Last Activity: 10 Years ago
Sol. S = 100 m, t = 10.54 sec, m = 50 kg
The motion can be assumed to be uniform because the time taken for acceleration is
minimum.
a) Speed v = S/t = 9.487 e/s
So, K.E. = ½ mv^2 = 2250 J
b) Weight = mg = 490 J
given R = mg /10 = 49 J
so, work done against resistance WF = – RS = – 49 × 100 = – 4900 J
c) To maintain her uniform speed, she has to exert 4900 j of energy to over come friction
P = W/t = 4900 / 10.54 = 465 W