Question

A 60 kg man running on horizontal road and increases his speed from 2ms−1 to 6 ms−12ms−1 to 6 ms−1. During this period work done by friction on the man :

Answer 1

Mass=60kg

Change in velocity(1st)6-2=4m/s

P1=mv1=240

Ke1=p2/2m=240×240÷120=480

V2=6m/s

P2=360

Ke2=980

Ke3=-980

Work total done=480j