Question

An object mass 10 kg moving in straight path changes its speed from 54 kmph
to 108 kmph in 10 seconds. Find work done by the external force. ​

Answer 1

Answer:

3375 joules

Explanation:

f=ma

= 10x(v-u)/t

=10x(30-15)/10 {54km/hr=15m/s & 108km/hr=30m/s}

f =15 N (a=1.5m/s^2)

W=force x displacement

now, finding displacement...

s=ut+1/2at^2

=15x10+1/2x1.5x10x10

=150+75

=225m

so, W= fd

=15x225

=3375 Joules.

hope u understand:)