I know how to do this problem, but the thing that is throwing me off are the units I have to answer in. Can anyone tell me how to go about solving this? Thanks all 
A team of dogs drags a 150 kg sled 3.14 km
over a horizontal surface at a constant speed.
The coefficient of friction between the sled
and the snow is 0.123.
The acceleration of gravity is 9.8 m/s2 .
a. Find the work done by the dogs.
Answer in units of kJ.
b. Find the energy lost due to friction.
Answer in kJ.
A team of dogs drags a 150 kg sled 3.14 km
over a horizontal surface at a constant speed.
The coefficient of friction between the sled
and the snow is 0.123.
The acceleration of gravity is 9.8 m/s2 .
a. Find the work done by the dogs.
Answer in units of kJ.
b. Find the energy lost due to friction.
Answer in kJ.