There's a box, held in place by friction, which rides on the flatbed of a truck, which is traveling at a constant speed v. The truck is riding on a circular road, going clockwise. For the diagram, please click here: http://i3.photobucket.com/albums/y92/musicis4fools2/physics3arrows.jpg
My question is, which way does static friction (fs) point towards? I already know which direction the normal force and gravity is, but I'm a little lost on which way static friction goes... on the diagram, is it in the direction of the blue, green, purple, or pink arrow?
2006-11-26 05:21:03 · 5 answers · asked by paulinatran10 1 in Science & Mathematics ➔ Physics
It is the green arrow toward the center of the circle as the frictional force is the force preventing the box from sliding off the outside of the truck. the frictional force is always in the opposite direction of a motion. think of it as the force that fights you when you slide a box on a surface. it does not matter which way you slide the box the friction is always against you. and since you can feel the force pulling you toward the outside when you in a vehicle going around a corner the friction between you and the seat it always pulling you toward the inside. Unless you have armor all'ed the seat, then you go flying!
2006-11-26 05:58:37 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Friction is always in opposition to relative motion. When going in a circle, the box's inertia is wanting it go go the direction of it's velocity (the purple arrow). The only force that is acting on the box to prevent this is the friction between the box and the flatbed. The friction is pulling the box towards the center of the circle. In this case, friction is the centripital force as far as the box is concerned. So the friction would be the green arrow.
To prove this, assume there is no friction all of a sudden? The box will continue to travel along the purple arrow.
Note that relative motion and velocity are not the same here. If friction dissapeared, the velocity of the box would be in the direction of the purple arrow. But relative to the box's point of view, the motion along the flat bed would be along the pink arrow as the truck continued to turn.
Basically, if you were to draw another diagram a second after the box began to slide and the purple arrow was not moved, the box would continue to move along the purple arrow, but the truck and the pink arrow would have moved. http://i115.photobucket.com/albums/n287/super_ag/diagram.gif
From the whole perspective, the box travelled along the purple line. From the truck's perspective, the box traveled along the pink line. The relative motion then is in the direction of the pink line, so the friction is in the opposite direction along the green arrow.
2006-11-26 14:48:29 · answer #2 · answered by Spaghetti Cat 5 · 0⤊ 0⤋
Since the truck is traveling in a circle, the truck and everything in it must be accelerating (although they are at a constant speed).
Since the box in the truck is not slipping, some force must be acting on it to accelerate it....this force is the force of [static] friction.
Think about how the box is accelerating and what type of force must be acting on it?
It is Centripetal force. The centripetal force (as provided by the force of friction) must be pointing inward towards the center of rotation in order to cause uniform circular motion.
2006-11-26 13:30:26 · answer #3 · answered by mrjeffy321 7 · 1⤊ 0⤋
i believe that it is toward the center of the circle....known as the centripital force.
2006-11-26 13:29:19 · answer #4 · answered by warguy2000 2 · 0⤊ 0⤋
pink
acceleration (centripetal) is towards the center.
Static friction opposes that.... I think :)
2006-11-26 14:08:31 · answer #5 · answered by CL 2 · 0⤊ 2⤋