a ball is thrown upwards from the ground at a tower with speed of 20m/s the tower has many windows each at a distance of 4m and the first one at 4m height from the ground. find how many windows can be used to see the balls motion. how many times does the ball cross the first window
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Answer:
ANSWER
Let the ball dropped down is a and the ball thrown up is b. also the stone thrown upwards cover a distance of x and the other covers a distance of (100 –x).
For ball a
u=0
g=10m/s
2
d=(100−x)
Using the equation
s=ut+
2
1
at
2
100−x=5t
2
.........(1)
For ball b
d=x
g=−10m/s
2
u=25m/s
s=ut+
2
1
at
2
x=25t−5t
2
............(2)
Solving equation (1) and (2)
100=25t
t=4seconds
Put the value of t in equation (1)
x=100−80
x=20m
They will meet at distance of 80 m from the ground after t = 4 seconds
I hope you understand my answer