Question

A 2 kg mass starts from rest on an inclined smooth surface with inclination 30^o and length 2 m. How much will it travel before coming to rest on a frictional surface with frictional coefficient of 0.25

• A. 4 m
• B. 6 m
• C. 8 m
• D. 2 m

Answer 1

Answer: (A)

4 m

Answer 2

$v ^ { 2 } = u ^ { 2 } + 2 a s = 0 + 2 \times g \sin 30$ $\times 2$ ⇒ $v = \sqrt { 20 }$

Let it travel distance ‘S’ before coming to rest

$S = \frac { v ^ { 2 } } { 2 \mu g } = \frac { 20 } { 2 \times 0.25 \times 10 } = 4 \mathrm {~m}$