1.

A ball is dropped from the top of a building. The ball takes 0.5s to fall past the 3m height of a window some distance from the top of the building. If the speed of the ball at the top and at the bottom of the window are VT and VB respectively then PLEASE GIVE DETAILED SOLUTION OF THE D3QUESTION IN THE ATTATCHMENT

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)

We have given, the speed of the ball at the top of the window = VT and 

and the speed of the ball at the bottom of the window = VB

The acceleration we know is ‘g’, g = 9.8 m/s 

The me taken to cross the window, t =0.5 s and the length of the window is S = 3 m. 

We have, V2-U= 2g(3) 

also, V = U+g(0.5) i.e VB-VT = 0.5g 

(VB+VT)(VB-VT) = 6g 

(VB+VT)(0.5g) = 6g 

VB+V= 12 m/s,

VT-V= -4.9 m/s

So option (A) is correct i.e VB+V= 12 m/s



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