Question

7. A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m 52, with
what velocity will it strike the ground ? After what time will it strike the ground ?

Answer 1

Answer: Sol:↓

Explanation:

data; u=O, s= 20, a=g=10m/s^2

By 3rd kinematic equation

v^2 = 2 g s

v^2 = 2× 10× 20

v^2 = 400

v = (root 400)

v = 20m/s

now, By second kinematic equation

s = 1/2 g t^2

20 = 1/2 × 10 × t^2

20 = 5 × t^2

20÷ 5 = t^2

4 = t^2

(root 4)= t

t = 2s

1) At velocity 20m/s it will strike the ground.

2) After 2s it will strike the ground.

Note:( that we are considered u = 0, I used kinematic equation made from newtons equations of motion.)

------ Amann-------

Answer 2

Explanation:

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