What Force Must Be Exerted at 35 Degrees on a 30 Degree Hill?

[Hitokiri]

"Respect" Newton question

Ok here's the question:

A boy drags a 100-N sled up a 20 degree slope at constant velocity. If the coefficient of friction between sled and hill is 0.2, what force must he exert at an angle of 35 degree with respect to the hill?


Ok, I've done the FBD and summed up the forces of the 20 degree. The part where i have the most trouble is understanding what they mean by "respect to the 30 degree hill". Does this mean i carry the friction, tension, or what?

Thanks

 

[HallsofIvy]

There is no 30 degree hill!

The wording is "what force must he exert at an angle of 35 degree with respect to the hill?". The "with respect to" here just means that the 35 degrees is measured from the hill, not the horizontal. Since the hill is 20 degrees from the horizontal, that means the force is actually being applied 55 degrees from the horizontal.

I recommend you divide all forces into components parallel to and perpendicular to the hill.

 

[Hitokiri]

ooo ok i see how you do it, thanks