Question

a man rowing boat upstream is at rest with respect to the shore. is he doing work?​

Answer 1

Explanation:

the boat is at rest with respect to the source but it is moving upstream with respect to water.The man is doing work relative to the stream because he is applying force to produce relative motion between the boat and stream.But he does no work relative to the shore as displacement relative to the shore is zero.

Answer 2

Answer:

Yes, the boat is doing work against the river current but there is no work done by boat against shore because there is no displacement taking place with respect to shore.