11. a student lifts a 25 kg mass a vertical distance of 1.6 m in a time of 2.0 seconds.
a. find the force needed to lift the mass (in n).
b. find the work done by the student (in j).
c. find the power exerted by the student (in w).

a) 245 N

b) 392 J

c) 196 W

Explanation:

a) Force needed to lift the 25 kg object is the same as the weight of the object:

b) Work is the force exerted times the distance moved:

c) The power exerted is the quotient of the work done over the amount of time it took to move the object:

you would expect a sound wave to speed up. - b)