Question

A body of mass 1 kg starts from rest and attains
a speed of 10 m/s in 5 s. The average power
expended by the body is​

Answer 1

Answer:

First find the acceleration.

Vf =vi +at

10 = 0+a×5

a=10/5

a = 2 m/s ²

Now find force

F = ma

F = 1×2

F 2 N

now find power.

P = F. v

P = 2 ×10

P = 20 Watt.

Answer 2

10

m=1kg ; u = 0m/s

v = 10m/s t = 5s

power = work (energy/time)

a = v-u/t

a= [10-0]/5 =2m/s

v^2 - u^2 = 2as

s = 10^2 /2(2)

s= 100/4 =25

now

PE = F* S

PE = ma*s

PE = 1*2*25 = 50Nm

Now P = PE/t

P = 50/5

Power = 10 wt