a stone dropped from the ground a height of 45m above the ground calculate the velocity of the ball just before it strike the ground neglect air resistance and the g=10m/so

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Explanation:

Under the assumptions, the acceleration of this ball would be constant during the descent. Thus, the SUVAT equations would apply.

Let denote the displacement of this stone during the fall. Let and denote the velocity of this ball at the beginning at the end of the fall, respectively. Let denote the acceleration of this ball. The SUVAT equation would apply.

Rearrange the equation to find an expression for , the velocity of this ball at the end of the fall:

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If the final velocity of the ball is in the same direction as the displacement (downwards), then , such that .

The acceleration of this ball during the fall should be equal to the gravitational field strength: .

The displacement of the ball during the fall would be .

The question states that the ball was "dropped" from the given height. Thus, the initial velocity of the ball would be . (That is, .)

Substitute these values into the expression for and evaluate:

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Therefore, the velocity of this ball right before landing would be .

weight of the box is given as

here this is placed on the inclined of angle 42 degree

now this weight will have two components one is along the incline other is perpendicular to it

so here we need to apply a force parallel to incline opposite to its component of weight

so here the component of weight is given as

here we have

so it requires 75 n force to move it upwards

it is b. absorbs thermal energy