4. A weightlifter raises a mass mat a constant speed to a height h in time t. Which of the following expressions corresponds with the work done by the weightlifter?
a. mgh
b.-mgh
C. mgh/t
d. -mgh/

Explanation

The work done by the lifter is equal to its potential energy since he is covering a height and under the influence of gravity.

potential energy = mass * acceleration due to gravity * height

m is the mass

g is the acceleration due to gravity

h is the height

Hence the required workdone = PE = mgh

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