A man is pulling a 13-kg sled across a flat, snowy surface. He holds the handle of the sled at a 30° angle with the ground.

What is the minimum pulling force (F) to the nearest newton that the man must exert to keep the sled moving? (Use the following constants: coefficient of sliding friction = 0.15; acceleration due to gravity = 9.8 m/s2, cos 30 = 0.87.)

Question

A man is pulling a 13-kg sled across a flat, snowy surface. He holds the handle of the sled at a 30° angle with the ground.

What is the minimum pulling force (F) to the nearest newton that the man must exert to keep the sled moving? (Use the following constants: coefficient of sliding friction = 0.15; acceleration due to gravity = 9.8 m/s2, cos 30 = 0.87.)

anonymous · Answer

they didn't give you the value of sin 30, also ?

ksaimouli · Answer

yes they did not

anonymous · Answer

I think they want you to do the problem incorrectly then.

anonymous · Answer

where's this problem from?

ksaimouli · Answer

hm

anonymous · Answer

whatever,  just do: us*mg = Fcos(30)
                                  (.15*13*9.8)/.87 =F

ksaimouli · Answer

mg is weight right so their should be normal force too

ksaimouli · Answer

|dw:1349046812767:dw|

anonymous · Answer

not really.

anonymous · Answer

he's pulling up on the sled as well as to the right.
this means the normal force is reduced.