Question

Calculate the Work done ; If work done is zero , give reasons.

a)A man carrying a load of 5kg on his head and moving forward with a velocity 5m/s

b)A child of mass 35kg riding a bicycle with velocity 36 km/hr

Answer 1

Hello deepu,

a.) Here in this situation the force exerted in perpendicular to the direction of displacement due to which work done is zero as cos 90 degrees= 0.

b.)Given,

Mass of child = 35kg

velocity= 36km/hr
=10 m/s

work done here is in the form of kinetic energy.

Therfore work done = 1/2 mv^2

=1/2 x 35 x (10)^2
=1/2 x 35 x 100
=35 x 50
=1750 Joules.

hope it helps u.........