Question

A long platform of infinite mass is moving horizontally with a velocity of 6 m s^–1. A 10 g small block is gently lowered on it. The coefficient of friction between the block and the platform is 0.3. The distance moved by the block before coming to rest with respect to the platform is -[Take g = 10 ms^–2]

• A. 3 m
• B. 6 m
• C. 12 m
• D. 18 m

Answer 1

Answer: (B)

6 m

Answer 2

t = $\frac { \mathrm { v } - \mathrm { u } } { \mu \mathrm { g } }$ = $\frac { 0.6 } { 0.3 \times 10 }$ =2 sec.

s = v_avg. × time

= $\left( \frac { 6 + 0 } { 2 } \right)$ × 2= 6 m