First slide

Projectile motion

Question

A ball rolls off the top of a stairway horizontally with a velocity of 4.5 ms^-1. Each step is 0.2 m high and 0.3 m wide. If g is 10 ms^-2, and the ball strikes the edge of n^th step, then n is equal to

Moderate

A

9
B

10
C

11
D

12

Solution

$\begin{array}{l} 0 .2 n = \frac{1}{2} {gt}^{2} or t = \sqrt{\frac{2 \times 0 .2 n}{g}} \\ 0 .3 n = ut = 4 .5 \sqrt{\frac{2 \times 0 .2 n}{g}} \\ \Rightarrow n = 9 \end{array}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App