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2 years ago

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Neglecting the effect of air resistance a stone dropped off a 175-m high building lands on the ground in: A)3s B)4s C)6s D)18s E

)36s

1 answer:

Bad White [126]2 years ago

5 0

Answer:

c) 6s

Explanation: take downwards as positive.

let vf = the velocity of the stone when it hits the ground, vi = 0 be the starting velocity of the stone. r0 = 175m be the height of the building.

(vf)^2 = (vi)^2 + 2g(r-r0)

(vf)^2 = 2g(r0)

vf = \sqrt{2g(r0)}

= \sqrt{2×9.8×(175)}

= 58.6 m/s

then:

vf = vi + g×t

vf = g×t

t = vf/g

= (58.6)/(9.8)

= 6s

Therefore, it will take the stone 6 seconds to reach the gound.

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The static friction exerted on the block by the incline is $\mu _ s _1 Mgcos \ \theta$ .

The given parameters;

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The normal force on the block is calculated as follows;

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The static friction exerted on the block by the incline is calculated as follows;

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Answer:

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