Question

a body of mass 10kg initially at rest acquires velocity of 10m per s what is the work done

Answer 1

Work done = kinetic energy K.E.= 1/2 mv^2 W= 1/2 * 10* 10 * 10 W = 500J

Answer 2

Given: mass of the body- m  = 10kg

            initial velocity- u = 0 (at rest)

            final velocity - v = 10m/s

To Find: work done - W = ?

Solution:

Formulas used:

• Work energy theorem - the difference of kinetic energy gives work done.
• ΔW = K' - K (K' = final kinetic energy, K = initial kinetic energy)
• Kinetic energy = 1/2 × m × v²

Applying the above formulas:

ΔW = 1/2 × m × v² - 1/2 × m × u²

ΔW = 1/2 × 10 × 10² - 1/2 × 10 × 0²

ΔW = 1/2 × 10 (10² - 0²)

ΔW = 5 × 10²

ΔW = 500J

Hence, work done by the body = 500J