a. For crates sliding down at constant speed along the x axis (see figure), the friction force F should be balanced by the projection of the gravity force on the x axis, that equal .
Friction force is ,
where (reaction of the incline plane),
- coefficient of sliding friction, wich for sliding of wood on wood is 0.48.
,
b. To start a 100 kg crate sliding down the incline plane the pushing force should reach the value of static friction force, that is
where - coefficient of static friction, wich for wood on wood is 0.62.
So,
Answer: a: 26 deg, b: 546.7 N.
Comments
Leave a comment