A girl pushes a wheelbarrow by exerting a 127N force horizontally She moves it 54 m at a speed of 29 sec?

Question

How much power in Watts does she develop? And if she moves the wheelbarrow 5.4 times as fast how much power in Watts is develped?

Answer 1

Power is the rate of doing work.
P - Power.
F - Force.
d - Distance.
t - time.

P = [F*d]/t
P = [127*54] / 29
P = 236∙482 7586
P ≈ 236∙48

Old speed = 54/29
Old speed = 1∙862 068 966

New speed = Old speed * 5∙4
New speed = 1∙862 068 966 * 5∙4
New speed = 10∙055 17241

P = [F*d]/t
P = 127 * 10∙055 17241
P = 1277∙001 6897
P ≈ 1277∙00 Watts.

Answer 2

Power (in Watts) is given in Energy (in Joules) per unit time (in seconds).

Energy (in Joules) is given by Force (in Newtons) multiplied by distance (in meters).

So in your case,

Energy = (127 N)*(54 m) = 6858 Joules

Power = (6858 Joules)/(29 seconds) = 236.483 Watts


If she moves it 5.4 times as fast, then she'll move 54 meters in (29/5.4) seconds. In other words, she'll move 54 meters in 5.37 seconds. In that case,

Power = (6858 Joules)/(5.37 seconds) = 1277.01 Watts


Note that (1277.01 Watts) = 5.4*(236.483 Watts). In other words, an increase in speed corresponds to the same increase in power. Power is directly proportional to speed.

Answer 3

127*54=6858 J
6858J/(29/60)=14188.96W
Approximately =14200W
=1.42KW
(b)1.42*5.4=7.668KW