A girl having a mass of 35 kg sits on a trolley of mass 5 kg. The trolley is given an initial velocity of 4 ms–1 by applying a force. The trolley comes to rest after traversing a distance of 16 m. How much work is done on the trolley ?

Foundation

Physics Foundation

Work Power Energy

Force and Newtons Law of Motion

Impulse and Momentum

Question

A girl having a mass of 35 kg sits on a trolley of mass 5 kg. The trolley is given an initial velocity of 4 ms^–1 by applying a force. The trolley comes to rest after traversing a distance of 16 m. How much work is done on the trolley ?

120 J

0 J

250 J

320 J

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Given,

Mass of the girl, m_g = 35 kg

Mass of the trolley, m_t = 5 kg

Iniial velociy, u = 4 ms^–1

Final velocity, v = 0

Displacement, s = 16 m

Total mass, m = m_g + m_t

m = 35 + 5 = 40 kg

Using Newton's second equation of motion,

S = ut + \frac{1}{2} u^{2}

\Rightarrow a = \frac{v^{2} - u^{2}}{2 s}

a = - \frac{0^{2} - 4^{2}}{2 \times 16}

a = – 0.5 ms^–2

Force, F = ma

F = 40 × (–0.5)

F= – 20 N

Magnitude of force, F = 20 N

Work done on the trolley, W = (20 × 16) J

W = 320 J