Question

3 A man pushes a 25 kg pram up a slope as shown in the diagram.
He pushes with a force of 150 N along the 20 m slope. How much energy is
dissipated as thermal energy?
A 250 J
B 500 J
C 2000 J
D 2500 J

Answer 1

Answer:

I think it's B)500J

Explanation:

Hope this helps

Answer 2

In the question total work done is
W= force x displacement
= 150x 20
=3000 J

But we know that work is done against weight and against frictional force
Work done against friction is dissipated as thermal energy

So resolving g to components
g sin(Q) will be parallel to inclined plane

So we have work done = mg sinQ x S
= 25 x 10 x 10/20
=2500 J

So thermal energy dissipation = 3000-2500
=500 J

Answer is Option B