ANother force problem (Please offer any help you can)

[avb203796]

A horse plls a sleigh via a rope that makes an angle of 15 degrees above the horizontal. The sleigh has a mass of 300.0kg and the kinetic coefficient of friction between the sleigh and the snow is 0.15. If the sleigh moves at constatn velocity, how much work does the horse do as she drags the sleigh for 5.0 km? How much work is doen by friction? Hiow much work will be done by friction if the sleigh is dragged a distance of 1.0km, turned around, and then dragged 1.0 km in the opposite direction? Finally, if the sleigh is accelerated at 2.0 m/s^2, what is the tension in the rope and the work done on the sleigh by the horse over a distanc eof 0.1km?

I am not sure exactly where and how to begin!

 

[vaishakh]

Draw a free body diagram to get an easy breakthrough.
If the force applied by the horse is F, then the sleigh would move due to Fcos15deg. Fsin15deg would be applied against the weight of the sleigh. Thus the normal force would decrease by Fsin15deg and thus the kinetic friction force. I think now you must be able to solve.

 

[avb203796]

But how do I know what F is?

 

[mukundpa]

If the sleigh is moving with constant velocith the work done by the horce is against the friction only.

 

[vaishakh]

Don't you know the forceto be appliedif the sleigh has to move with constant velocity. That should exactly equal the friction force so that the netforce on the object is 0. Now can you continue?

 

[avb203796]

so does this mean that the force of the horse would be 441 or 441cos15deg

 

[mukundpa]

no nigther. Draw the diagram, consider the tension T in the rope, resolve T in horizpntal and vertical, make two equations for Hz and Vt forces to balance, find Normal reaction( not equal to mg). . . . ...