Question

A stone of 0.2 kg is projected vertically upward by expending 90 J of energy. How high the stone rises?
a.80m
b.75m
c.25m
d.45m​

Answer 1

Answer: 45m

Explanation:

mass= 0.2 kg

Energy= 90 J

Energy = 1/2 mv²

Therefore, 90J = 1/2×0.2 ×v²

v=√900v=30

velocity= 30 m/s

As per the formula,

v²-u²= 2as. (g=10 m/s²)

=>0²-30²= 2× (-10)s

=> -900 = -20s

=>s=45

Therefore , the stone will rise 45 metre high.

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