# ap physics

posted by .

A 1.20*10^2 kg crate is being pushed across a horizontal floor by a force P that makes an angle of 30.0° below the horizontal. The coefficient of kinetic friction is 0.350. What should be the magnitude of P, so that the net work done by it and the kinetic frictional force is zero?

• ap physics -

So P is pointing UP?

If so, a portion of P counters weight, and in so doing, reduces friction to zero.

Psin30=mg
P= 2mg

• ap physics -

If the net force is zero, the friction force balances the horizontal component of the applied force P.

Calculate the Friction force and divide it by cos 30.

The fact that the applied force is 30 deg below horizontal will affect the friction force.

• ap physics -

My interpretation of the problem is different from Bob's. I did not assume that the friction was reduced to zero, only that it balances the applied force to make the net force (and work) zero.

## Similar Questions

1. ### physics

A 1.20*10^2 kg crate is being pushed across a horizontal floor by a force P that makes an angle of 30.0° below the horizontal. The coefficient of kinetic friction is 0.350. What should be the magnitude of P, so that the net work done …
2. ### physics

A 1100 N crate is being pushed across a level floor at a constant speed by a force of 500 N at an angle of 20.0° below the horizontal. (a) What is the coefficient of kinetic friction between the crate and the floor?
3. ### physics

A 1,440-N crate is being pushed across a level floor at a constant speed by a force of 210 N at an angle of 20.0° below the horizontal, as shown in the figure (a) below (a) What is the coefficient of kinetic friction between the crate …
4. ### Physics

A 1.00e2kg crate is being pushed across a horizontal floor by a force of P that makes an angle of 30.0 degrees below the horizontal. The coefficient of Kinetic Friction is 0.200. What should be the magnitude of P, So that the network …
5. ### physical aspects of nature

A 1,440-N crate is being pushed across a level floor at a constant speed by a force of 250 N at an angle of 20.0° below the horizontal; (a) What is the coefficient of kinetic friction between the crate and the floor?
6. ### physics

A 1,040-N crate is being pushed across a level floor at a constant speed by a force of 350 N at an angle of 20.0° below the horizontal; (a) What is the coefficient of kinetic friction between the crate and the floor?
7. ### physics

A 1,080-N crate is being pushed across a level floor at a constant speed by a force of 290 N at an angle of 20.0° below the horizontal, as shown in the figure (a) below. (a) What is the coefficient of kinetic friction between the …
8. ### Physics

A 1.60 102-kg crate is being pushed across a horizontal floor by a force that makes an angle of 30.0° below the horizontal. The coefficient of kinetic friction is 0.200. What should be the magnitude of , so that the net work done …
9. ### Physics

A 250-kg crate is being pushed across a horizontal floor by a force P that makes an angle of 30.8 ° below the horizontal. The coefficient of kinetic friction is 0.224. What should be the magnitude of P, so that the net work done by …
10. ### Physic

A 287-kg crate is being pushed across a horizontal floor by a force P that makes an angle of 25.6 ° below the horizontal. The coefficient of kinetic friction is 0.236. What should be the magnitude of P, so that the net work done by …

More Similar Questions