A box full of books rests on a wooden floor. The normal force the floor exerts on the box is 250 N (newtons). (a) You push horizontally on the box with a force of 120 N, but it refuses to budge. What can you say about the coefficient of static friction between the box and the floor? (b) If you must push horizontally on the box with a force of at least 150 N to start it sliding, what is the coefficient of static friction? (c) Once the box is sliding, you only have to push with a force of 120 N to keep it sliding. What is the coefficient of kinetic friction?
2006-09-06 12:45:08 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Physics
a.
The coefficient of static friction is > .48
b.
The coefficient of static friction is 150/250 = .6
c.
The coefficient of kinetic friction is 120/250 = .48
BTW, in part c the magic words "with a constant velocity" really need to appear. If they don't, it could mean that the box is accelerating in which cast the coefficient of kinetic friction would be *less* than .48 ☺
Doug
2006-09-06 13:00:29 · answer #1 · answered by doug_donaghue 7 · 1⤊ 0⤋
a. you didn't push hard enough.
b. keep pushing.
c. The coefficient of kinetic friction is defined as
ff/fn = crazy symbol
where ff is the frictional force and fn is the normal force and crazy symbol is uhh, you know.
Does this help? Somehow I doubt it :)
2006-09-06 19:51:08 · answer #2 · answered by kookie 3 · 0⤊ 0⤋
a coefficient of static friction is more than 0.48.
b coefficient of kinetic friction=0.48.
2006-09-06 19:53:12 · answer #3 · answered by zee_prime 6 · 1⤊ 0⤋
Hey O N E question .... one answer. For things like that, go to math forum or do it just yourself !!
2006-09-06 20:00:47 · answer #4 · answered by jhstha 4 · 0⤊ 2⤋