This question was previously asked in

RRC Group D Previous Paper 25 (Held On: 22 Sept 2018 Shift 2)

Option 1 : 30 kJ

RRC Group D Full Mock Test

407098

100 Questions
100 Marks
90 Mins

__CONCEPT__:

**Work**is said to be done when a force applied on an object causes displacement of the object.

Work done (W) = force (F) × displacement (S)

- Work-energy theorem: It states that the sum of work done by all the forces acting on a body is equal to the change in the kinetic energy of the body i.e.,

Work done by all the forces = Kf - Ki

\(W = \frac{1}{2}m{v^2} - \frac{1}{2}m{u^2} = {\bf{Δ }}K\)

Where v = final velocity, u = initial velocity and m = mass of the body

__CALCULATION__:

It is given that,

Mass (m) = 800 kg

Final Velocity (v) = 10 m/s and initial velocity (u) = 5 m/s

According to the work-energy theorem,

⇒ Work done = Change in K.E

⇒ W = Δ K.E

\(W = \frac{1}{2}m{v^2} - \frac{1}{2}m{u^2} = {\bf{Δ }}K\)

⇒ W = 1/2 × 800 × (10^{2 }- 5^{2})

⇒ W = 400 × 75

⇒ W = 30000 J

⇒ **W = 30 kJ**