5.13 A box is pushed at a constant velocity 10 m along a floor. The frictional force between the box and the floor is 120 N. At what rate must work be done on the box to complete the push in: (a) 60 s (b) 45 s (c) 30 s (d) 10 s (e) 5 s (f ) 1 s

A 7.80-g bullet moving at 470 m/s penetrates a tree trunk to a depth of 6.50 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the friction force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment in stops moving.

A 7.80-g bullet moving at 460 m/s penetrates a tree trunk to a depth of 4.90 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (Enter the magnitude.) (b) Assuming the friction force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.

I need help with part D!!

11. A 5kg block is pushed up a 40° incline at constant velocity of 3m/s. The force pushing on the blockacts parallel to the incline, and has a magnitude of 47.5N. (a) What is the magnitude of the normal forceacting on the block? (b) What is the magnitude of the frictional force? (c) Calculate the coefficient offriction. (d) How much work is done by the normal force? (e) How much work is done by the force offriction after 4 seconds have elapsed? (f) What is the net work done on the block?

A 7.80-g bullet moving at 570 m/s penetrates a tree trunk to a depth of 4.40 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (b) Assuming the frictional force is constant, determine how much time elapses between the moment the bullet enters the tree and the moment it stops moving.

A 40.5 kg box initially at rest is pushed 4.40 m along a rough, horizontal floor with a constant applied horizontal force of 125 N. If the coefficient of friction between box and floor is 0.300, find the following. (d) the work done by the gravitational force J(e) the change in kinetic energy of the box J(f) the final speed of the box m/s

Calculate the minimum amount of work needed to move a 400 kg rocket from Earth's surface to the International Space Station in orbit 300,000 m above Earths surface. Solve for the minimum amount of work needed to move the payload to the ISS. Start with general equations and explain what you are doing and why you did what you did. Evaluate your solution. Describe how you evaluated your answer and whether or not you think your answer is reasonable.

A hummingbird hovers by exerting a downward force on the air equal, on average, to its weight. By Newton's third law, the air exerts an upward force of the same magnitude on the bird's wings. Find the average mechanical power (in W) delivered by a 3.60 g hummingbird while hovering if its wings beat 75.0 times per second through a stroke 3.98 cm long. HINT To find the average power per stroke, calculate the work done each stroke and divide by the time per stroke. Click the hint button again to remove this hint.

Two shuffleboard disks of equal mass, one orange and the other green, are involved in a perfectly elastic glancing collision. The green disk is initially at rest and is struck by the orange disk moving initially to the right at vOi = 5.80 m/s as in Figure a, shown below. After the collision, the orange disk moves in a direction that makes an angle of ? = 34.0° with the horizontal axis while the green disk makes an angle of ? = 56.0° with this axis as in Figure b. Determine the speed of each disk after the collision.