Answer:
Power output, P = 3800 watts
Explanation:
It is given that,
Work done by the lawnmover engine, W = 4560000 J
Time taken, t = 20 min = 1200 sec
We have to find the power output of the engine. Power of an engine is given by work done per unit time taken i.e.
P = 3800 Watts
Hence, the power output of the engine is 3800 watts.
a) c = 1.85
b) c = 0.8
c) c = 2.33
Explanation:
a)
The displacement of the particle is given by
While the force applied on the particle is
So we have a problem in 2-dimensions.
The work done on the particle is given by the scalar product between force and displacement:
(1)
Here the work done on the particle is zero, so
W = 0
Therefore from eq(1) we find:
b)
In this problem, the work done on the particle is
The force and displacement are still
(displacement)
(force)
Therefore, by calculting the scalar product between force and displacement and equating it to the work done (4.0 J), we find:
c)
In this problem instead, the work done on the particle is negative:
As before, the force and displacement are
(displacement)
(force)
And so again, we calculate the scalar product between force and displacement and we equate it to the work done on the particle, -1.8 J.
Doing so, we find: