Home
Class 11
PHYSICS
A ball is thrown vertically upwards from...

A ball is thrown vertically upwards from the ground and a student gazing out of the window sees it moving upward past him at `10ms^-1.` The window is at 15 m above the ground level. The velocity of ball 3 s after it was projected from the ground is [Take `g= 10 ms^-2`]

A

`10 m//s,` up

B

`20 m//s,` up

C

`20 ms^-1,`down

D

`10 ms^-1,` down

Text Solution

Verified by Experts

The correct Answer is:
D
Total height=`15+(u^2)/(2g)`
`=15+((10)^2)/(2xx10)`
or `h=20m`
initial velocity `u=sqrt2gh`
`sqrt(2xx10xx20)`
`=20 m//s`
Now applying `v=u+at,` we have
`v=(+20)+(-10)(3)`
`:.` Velocity is `10m//s,` downwards.
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • KINEMATICS

    DC PANDEY|Exercise Subjective|51 Videos

  • KINEMATICS

    DC PANDEY|Exercise More Than One Correct|6 Videos

  • KINEMATICS

    DC PANDEY|Exercise Assertion And Reason|12 Videos

  • GRAVITATION

    DC PANDEY|Exercise (C) Chapter Exercises|45 Videos

  • KINEMATICS 1

    DC PANDEY|Exercise INTEGER_TYPE|15 Videos

Similar Questions

Explore conceptually related problems

A football is kicked vertically upward from the ground and a student gazing out of the window sees it moving upwards past her at 5.00 m//s. The window is 15.0 m above the ground. Air resistance may be ignored. Take g=10 m//s^2. (a) How high does the football go above ground? (b) How much time does it take to go from the ground to its highest point?

A ball thrown up vertically returns to the ground after 12.5 second. Find the velocity with which it was thrown up? ( g = 10 ms^(-2) )

Knowledge Check

  • A ball is thrown vertically upwards from the top of tower of height h with velocity v . The ball strikes the ground after time.

    A
    `v/g[1+sqrt(1+(2gh)/(v^(2)))]`
    B
    `v/g[1+sqrt(1-(2gh)/(v^(2)))]`
    C
    `(v)/(g)(1+(2gh)/(v^(2)))^(1//2)`
    D
    `(v)/(g)(1-(2gh)/(v^(2)))^(1//2)`

  • A ball is thrown vertically upwards from the ground. It crosses a point at the height of 25 m twice at an interval of 4 secs. The ball was thrown with the velocity of

    A
    20 m/sec
    B
    25 m/sec
    C
    30 m/sec
    D
    35 m/sec

  • A ball is thrown vertically upwards from the ground It crosses a point at the height of 25 m twice at an interval of 4 secs . The ball was thrown with the velocity of.

    A
    `20 m//sec`
    B
    `25 m//sec`
    C
    `30 m//sec`
    D
    `35 m//sec`

    • Similar Questions

    Explore conceptually related problems

    A ball is thrown vertically upwards with a velocity of 20 ms^(-1) from the top of a multistorey building. The height of the point from where the ball is thrown is 25 m from the ground. How long will it be before the ball hits the ground (Take, g=10 ms^(-2) ) ?

    An object is thrwon vertically upwards with a velocity of 60 m/s. After what time it strike the ground ? Use g=10m//s^(2) .

    A body is thrown vertically upward from a point A 125 m above the ground. It goes up to a maximum height of 250 m above the ground and passes through A on its downward journey. The velocity of the body when it is at a height of 70 m above the ground is (g=10 m//s^(2))

    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 particle is thrown vertically upward from the ground with some velocity and it strikes the ground again in time 2 s. The maximum height achieved by the particle is : (g=10 m//s^(2))

    Home
    Profile