+91-8076753736 [email protected]

-->

Physical World

Question

Wired Faculty App

A ball is thrown upwards, it takes 4sec to reach back to the ground. Find its initial velocity

30ms^-1

10ms^-1

40ms^-1

20ms^-1

Solution

D.

20ms^-1

Since the ball is thrown upwards and it reaches back, so time to reach maximum height is half of the total time i.e

t_maximum = 2sec

Also speed at maximum height is zero, so

$0 = u - {gt}_{\max} \Rightarrow u = {gt}_{\max} = 20 {ms}^{- 1} (since g = 10 {ms}^{- 2})$

Some More Questions From Physical World Chapter

Dimension of relative density is

Mock Test Series

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation