A ball is gently dropped from a height of 20 m. If its velocity increases uniformly at the rate of 10 m s-2, with what velocity will it strike the ground? After what time will it strike the ground?
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Answered by
6
Answer:-
Given:-
- Distance it covered (s) = 20 m
- Initial velocity (u) of the ball = 0 m/s [Hidden]
- Acceleration (a) of the ball = 10 m/s²
To Find:-
Final velocity of the vall. (v)
__________...
We know,
2as = v² - u²
➽ v² = 2as + u²
➽ v = √2as (whole root)
[u = 0; 0² = 0]
∴ v = √2 × (10 m/s²) × 20 m
➵ v = √20 × 20 × m/s × m/s
➵ v = 20 m s^-1 ...(Ans.)
Best of Luck mate! :D
Answered by
22
Explanation:
Let us assume, the final velocity with which ball will strike the ground be ‘v’ and time it takes to strike the ground be ‘t’
Initial Velocity of ball, u =0
Distance or height of fall, s =20 m
Downward acceleration, a =10 m s-2
As we know, 2as =v2-u2
v2 = 2as+ u2
= 2 x 10 x 20 + 0
= 400
ˆ´ Final velocity of ball, v = 20 ms-1
t = (v-u)/a
ˆ´Time taken by the ball to strike = (20-0)/10
= 20/10
= 2 seconds
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