Forces and Angles Above The Horizontal (2 prob.)

[rwishka]

Homework Statement

1. A sled is pulled at a constant velocity across a horizontal snow surface. If a force of 8.0 x 10^1 N is being applied to the sled rope at an angle of 53 degrees to the ground, what is the force of friction between the sled and the snow?

A. 83 N
B. 64 N
C. 48 N
D. 42 N

2. A trapeze artist weighs 8.00x10^2 N. The artist is momentarily held to one side of a swing by a partner so that both of the swing ropes are at an angle of 30 degrees with the vertical. In such a condition of static equilibrium, what is the horizontal force being applied by the partner?

A. 924 N
B. 433 N
C. 196 N
D. 610 N

Homework Equations

I don't know any formulas to use for this.

The Attempt at a Solution

I'm sorry, but if I knew what formula to use, I could probably do it. I can't find any formulas that include angles in the section.

 

[cristo]

Try drawing diagrams, and resolving forces into components.

For the first question, since the velocity is constant, what can you say about the resultant horizontal force?

For the second question, again, what can you say about the resultant force?

 

[rwishka]

So, would it be F=80(cos 53 degrees). So F=48 N. Answer C, then?

For the second question, I did 800 = cos 30 degrees (F), so F = 924 N. Answer A.

Thank you SO much!