Question

A man weighing 80 kg is standing in a trolley weighing 320 kg. The trolley is resting on frictionless horizontal rails. If the man start walking on the trolley with a speed of 1 m/s, then after 4 s, his displacement relative to the ground will be -

• A. 5 m
• B. 4.8 m
• C. 3.2 m
• D. 3.0 m

Answer 1

Answer: (C)

3.2 m

Answer 2

Q Disp. of trolley w.r.t. ground,

x = $\frac{mL}{m + M} = \frac{80 \times 4}{80 + 320}$ = 0.8 m \m₁x₁ = m₂x₂

̃ 320 × 0.8 = 80x₂ ̃ x₂ = 3.2 m