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A 60.0-kg athlete jumps vertically upward

from the ground to a height of 0.910 m above

the ground. What was the athlete’s initial

vertical speed?

 

It's physics grade 10 and I just don't know what formula to use or how to solve these

4 years ago

Answered By Ryan H

Th0


4 years ago

Answered By Ryan H

The initial velocity is the unknown, desired quantity. Perhaps the thing the realize is: the final velocity is 0, at the given displacement. So we have a v, d, and a (is equal to g, the acceleration due to gravity), and we want to solve for vi.

The required equation is then:

vf2 = vi+ 2ad

vi = square-root( 0-(2*(-9.81)0.91)

Note that the acceleration due to gravity is given a negative sign here, as it's opposing the initial velocity, slowing the athlete to 0 m/s at the maximum height.

Note that the mass of the athlete is not used to solve the problem; we are close to the Earth's surface, and the force of gravity is not varying in this problem, so the acceleration is constant.