What is the work done by gravitation

[breakoutecho]

A skier lowers a cart 30m down a slope with a sontant speed. The cart has a mass of 90kg. The angle of the slope is 60 degrees. The coefficient of friction is 0.100.
A)Find the work done by friction as the sled moves down the hill.
B) how much work is done by the rope on the sled.
C) What is the work done by gravitation.
D) What is the total work done.

A) I already calculated friction, which was uN with N=mgcos , which gave me -1323J
But I am not sure about the next 3 parts
B) Would work be zero since speed is constant?

C) WG= FgD=mgd= (90kg) (9.8m/s2) is displacement 0m?

D) Would total work be zero, since speed is constant?

 

[ehild]

How is work defined?

ehild

 

[breakoutecho]

Work is Force * distance.

But since speed is constant, does that mean the total work is 0, since there would be no force?
Or would total work still be the addition of the separate works.

 

[ehild]

The total work of all the forces acting on the sled is zero, but the work of the separate forces is not.
Take care when calculating work. It is W=F d cos (theta), theta being the angle between the force F and displacement d.

ehild