Answer:
Explanation:
Total weight
My weight+weight of belongings
660+1100=1760N.
a. Work done by the elevator to travel a total height of 15.2m
Using newton law of motion
ΣF = ma
There are only two forces acting upward, the weight and the reaction by the elevator
Also note it is moving at constant velocity then, a=0
N - W=0
Then, N=W
N=1760N
So, workdone is given as
Wordone, =force × distance
Work done=1760×15.2
W=26,752J
W=26.752KJ
b. Work done on me alone is still need to go through the same process but will remove the weight of the belonging
Therefore,
Weight now = 660N
And using the same equation of motion
ΣF = ma
Comstant velocity, a=0
N - W=0
N=W
N=660N
Then, workdone
W=F×d
W=660×15.2
W=10,032J
W=10.032KJ
Answer:
A, 26752J
B, -10032J
Explanation:
See attachment below
Since the elevator is moving at a constant speed, we can then say
F(elev)=W(total)
While going up, the displacement is pointing upwards
W(up) = F*S = F*S cos0° = F*S
Since forces F and S point in the same direction, the angle in between them, thus is zero. We also know, F(elev) is the upward weight. Thus
W(up) = F*S = W(total)*S =
= (660N+1100N)*15.2m
= 1760N * 15.2m
= 26752J
While going downwards, the displacement S is pointing down and the weight going down is just the person, so we have
W(down) = F*S = F*S cos180° = -F*S
W(down) = -F*S = -W(total)*S
= -660 * 15.2
= - 10032J
Thus,
