What force pushes an object down an inclined plane?

1. What force pushes an object down an inclined plane?

2. A cart slides down a frictionless ramp as shown below.Which of the free-body diagrams below best represents the forces on the cart?

3. The steeper the incline the more force is needed to push the • object up it • The more massive the object the more force necessary to push it • up the incline

4. The steeper the incline the more of the skiers weight pushes down the incline *W sin  = mg sin   increases

5. FN w Normal Force = force perpendicular to surface When surface is horizontal the normal force equals the weight. FN = w cos q When surface is inclined the perpendicular direction is NOT vertical so the normal force is only a component of the object’s weight.

6.  // FN f  w cos  w link w sin  

8. FN f  w cos  w w sin   *W sin  pushes it down the incline*

9. Summary: • Part of the weight ( mg sin) pushes the object down the incline. • Part of the weight (mg cos) balances out the normal force. • The frictional force acts opposite the motion • To push something up an incline the minimum force necessary • is mg cos

10. If the mass of the block is 10 kg, and the coefficient of kinetic friction is .2, find the acceleration of the block down the incline.