Home
Class 12
PHYSICS
5A ball is thrown horizontally from a he...

5A ball is thrown horizontally from a height of 20 m. It hits the ground with a velocity three times its initial velocity. The initial velocity of ball is

A

`2m//s `

B

`3m//s `

C

`5m//s`

D

`7m//s`

Text Solution

Verified by Experts

Initial velocity is constant let the ball touches the ground at an angle `theta` and velocity 3u Hence` 3u cos theta = u or cos theta = 1//3 or sin theta =sqrt 8//3 `The vertical component of velocity at the ground

`=3u sin theta = root(3)(8)/(3) = sqrt8u`or fifty falling body i t cover 20 m to acquire velocity `sqrt8u`
`:. (sqrt 8 u)^(2)=0= 2xx20 or u= 7m//s`
Promotional Banner

Topper's Solved these Questions

  • PROJECTILE MOTION

    MOTION|Exercise EXERCISE-1|39 Videos

  • PROJECTILE MOTION

    MOTION|Exercise EXERCISE-2|22 Videos

  • PHOTOELECTRIC EFFECT

    MOTION|Exercise EXERCISE -3 (PREVIOUS YEAR PROBLEMS (JEE MAIN))|12 Videos

  • RADIOACTIVITY & NUCLEAR PHYSICS

    MOTION|Exercise Exercise-3|81 Videos

Similar Questions

Explore conceptually related problems

A ball is thrown horizontally from a height of 20m .If hits the ground with a velocity of 3 times the velocity of projection.The velocity of projection is 3.5x m//s then x is

A ball is thrown vertically upwards from a height of 40 m and hits the ground with a speed that is three times its initial seepd. What is the time taken (in sec) for the fall ?

A ball is thrown vertically down from height of 40 m from the ground with an initial velocity 'v'. The ball hits the ground, loses (1)/(3)rt of its total mechanical energy and rebounds back to the same height. If the acceleration due to gravity is 10 "ms"^(-2) , the value of 'v' is

A ball is thrown vertically upward with a velocity u from the top of a tower. If it strikes the ground with velocity 3u, the time taken by the ball to reach the ground is

A ball is thrown vertically upwards. It was observed at a height h twice after a time interval Deltat . The initial velocity of the ball is

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

A ball is dropped from a height of 20 m and rebounds with a velocity which is 3/4 of the velocity with which it hits the ground. What is the time interval between the first and second bunces (g=10m//s^(2))

A ball is thrown horizontally from a cliff such that it strikes the ground after 5s .The line of sight makes an angle 37^(@) with the horizontal.The initial velocity of projection in ms^(-1) is