find the solution for this:
A 240V dc shunt motor gives an output power of 25hp and draws an armature current of 80A at full load. Assume that the armature resistance is 0.05Ω and field resistance is 200Ω. Find the rotational losses at full load and motor efficiency.

 

We don't do your homework for you. What have you done so far besides post he question here?

 

Consider this: HP is just another way of expressing power.

You can convert the output power in HP to Watts.
You can also calculate the Electrical power input.
It should then be easy!