Answer:
Explanation:
Given that,
Mass of man =Mm=63kg
W=mg
W=63×9.81
W=618.03N
g=9.81m/s²
The escalator moves at a constant velocity, then this shows that it is not accelerating, then, a=0m/s²
Height escalator traveled
H=4.2m.
We assume that the weight of the escalator is negligible.
a. Work done by gravity
Work done by gravity is given as
Work done(gravity)=mgh
Since the work is done against gravity, then, g is negative
Then,
Work done(gravity)=-mgh
Work done(gravity)=-63×9.81×4.2
Work done(gravity)=-2595.726J
b. Work done by escalator
Using equation of motion to know the force pulling the escalator upward
ΣF = ma, but a=0
ΣF = 0
Only two force is acting on the in y axis, the Normal force and the weight
N-W=0
N=W
Since W=618.03N
Then, N=618.03
The normal is the force pulling the escalator upward
Then, the work done by escalator is given as
Work done=Force × distance
Work done=618.03×4.2
Work done= 2595.76J
Work done by escalator is 2595.76J
