1 A student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 sec
ID: 1369142 • Letter: 1
Question
1 A student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 seconds.
Find the force needed to lift the mass (in N).
Find the work done by the student (in J).
Find the power exerted by the student (in W).
2 A satellite is put into an orbit at a distance from the center of the Earth equal to twice the distance from the center of the Earth to the surface. If the satellite had a weight at the surface of 4000 N, what is the force of gravity (weight) of the satellite when it is in its orbit? Give your answer in newtons, N.
3 Consider a satellite in a circular orbit around the Earth.
Why is it important to give a satellite a horizontal speed when placing it in orbit?
What will happen if the horizontal speed is too small?
Explanation / Answer
Here,
mass of student , m = 25 Kg
height , h = 1.6 m
time , t = 2 s
let the force needed is F
F = 25 *(9.8)
F = 245 N
the force needed to lift the mass is 245 N
work done = m*g*h
work done = 245 * 1.6
work done = 392 J
the work done by student is 392 J
power exerted by student = work done/time
power exerted by student = 392/2
power exerted by student = 196 W
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