Question

A body sliding on a smooth inclined plane requires 4 seconds to reach the bottom starting from rest at the top. How much time does it take to cover one-fourth distance starting from rest at the top

• A. 1 s
• B. 2 s
• C. 4 s
• D. 16 s

Answer 1

Answer: (B)

2 s

Answer 2

$S = \frac { 1 } { 2 } a t ^ { 2 }$ ⇒ $t \propto \sqrt { s }$ $( A s \mathrm { a } =$ constant $)$

$\frac { t _ { 2 } } { t _ { 1 } } = \sqrt { \frac { s _ { 2 } } { s _ { 1 } } } = \sqrt { \frac { s / 4 } { s } } = \frac { 1 } { 2 } \Rightarrow$ $t _ { 2 } = \frac { t _ { 1 } } { 2 } = \frac { 4 } { 2 } = 2 \mathrm {~s}$