Question

A body of mass 5 kg is moving with velocity of 10 m/s  on a frictionless surface.If no external force is acting on the body then what will be it's momentum after 10 s?( ignore air resistance also) a) 50 kgm/s​

Answer 1

t=10sec

10=5×v[P=mv]

v=2m/s

As F=0.2N

a=50.2m/s2=251m/s2[a=mF]

at t=0,KE=21×s×(2)2[KE=21mv2]

KEi=10J

Now, at t=10sec, vf=u+at

vf=g+251×10=2.4m/s2

∴KEf=21×5×(2.4)2

=14.4J

∴△KE=14.4−10

=4.4J