Question

A ball is dropped from the top of a building the ball takes 0.5 sec to fall past the 3m length of a window some dis. from the top of building .if the velocities of the ball at the top and at the bottom of the window are vt and vb then

Answer 1

Answer:

A ball is dropped from the top of a building. The ball takes 0.5s to fall past the 3m height of a window som e distance from top of the building If the speeds are of the ball at top and bottom of the window are VT and VB respectively then (g=9.8m/s^2

As acceleration due to gravity g=9.8m/s^2

We can write VB=VT+ gt

=> VB- VT = 9.8x0.5 =5=4.9m/s .....(1)

VB^2-VT^2=2*g*3=2*9.8*3.....(2)

Dividing (2) by(1) we get

VB+VT =(2*9.8*3)/(4.9)=12m/s

Hence correct option is (A)