Question

17. A stone is allowed to fall from the top of a tower 100 m
and at the same time another stone is projected vert
upwards from the ground with a velocity of 25 m/s. calculate
when and where the two stones will meet​

Answer 1

Answer:

PHYSICS

A stone is allowed to fall from the top of a tower 100m high and at the same time another stone is projected vertically upwards from the ground with a velocity of 25m/s. Calculate when and where the two stones will meet.

October 15, 2019Omkar Kanchan

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VIDEO EXPLANATION



ANSWER

Let the stones meet at point A after time t.

For upper stone  :            

u′=0         

x=0+21gt2

x=½×10×t²         

⟹x=5t²         ............(1)

For lower stone :            

u=25  m/s  

100−x=ut−2gt²

100−x=(25)t−½×10×t²       

⟹100−x=25t−5t²        ............(2)

Adding (1) and (2),  we get          

25t=100              

⟹t=4 s        

From (1),            

x=5×42                 

⟹x=80 m 

Hence the stone meet at a height of   20 m above the ground after 4 seconds.