- #1
Hypnos_16
- 153
- 1
A 220-kg crate rests on a surface that is inclined above the horizontal at an angle of 18.3°. A horizontal force (magnitude = 501 N and parallel to the ground, not the incline) is required to start the crate moving down the incline. What is the coefficient of static friction between the crate and the incline?
The only real problem I'm having with this one is that i seem to have two variables
so far i have
Fnet = ma
mgsin18.3 + 501 x cos18.3 - Umgcos18.3 = ma
(220 x 9.8 x sin18.3) + (501 x cos18.3) - (U x 220 x 9.8 x cos18.3) = 220a
677 + 475.7 - U2046 = 220a
1142.7 - U2046 = 220a
though i don't even know if that's right, the cosine and sine sometimes mixes me up.
The only real problem I'm having with this one is that i seem to have two variables
so far i have
Fnet = ma
mgsin18.3 + 501 x cos18.3 - Umgcos18.3 = ma
(220 x 9.8 x sin18.3) + (501 x cos18.3) - (U x 220 x 9.8 x cos18.3) = 220a
677 + 475.7 - U2046 = 220a
1142.7 - U2046 = 220a
though i don't even know if that's right, the cosine and sine sometimes mixes me up.