Question

a stone is dropped from a top of cliff reaches ground level in 4s and then buries itself into 0.80m of mud calculate.
1) height of cliff
2) final velocity of stone on reaching ground level.
3) deceleration produce by mud ​

Answer 1

Answer:

Height h = 78.4 m

Final velo at ground = 39.2 m/s

Explanation:

Initial velo u = 0

Time taken = 4 s

deceleration = 960.4

1)

s = ut + 1/2 gt²

= 1/2 x 9.8 x 16

= 78.4 m

∴ Height of cliff = 78.4 m

2)

v = u + gt

= 9.8 x 4

= 39.2 m/s

∴ Final velo on reaching the ground = 39.2 m/s

3)

u = 39.2 m/s. v= 0. s = 0.8 m

v² -u² = 2as

- (39.2)² = 2 a x 0.8

a = - (39.2)²/1.6 = - 960.4 m/s²

∴ deceleration produced by mud = 960.4 m/s

Note : For mcq's use g = 10 m/s²

Answer 2

Answer:

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