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

I need help with part D!!

A 7.80-g bullet moving at 650 m/s penetrates a tree trunk to a depth of 5.80 cm. (a) Use work and energy considerations to find the average frictional force that stops the bullet. (Enter the magnitude.) N (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 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) A 1390 kg car accelerates uniformly from rest to 10.4 m/s in 2.87 s. Find the work done on the car in this time interval. Answer in units of kJ. B) Find the average power delivered by the en- gine in this time interval. Answer in units of hp. C) Find the instantaneous power delivered by the engine at t = 1.5 s. Answer in units of hp.

A 32-kg block is pulled along the ground for a distance of 4.9 m by a 57 N force at an angle of 21 degrees with respect to the horizontal. The coefficient of kinetic friction is 0.21. a)  Find the work done (in J) by the applied force. b)  Find the work done (in J) by the normal force exerted by the ground. c)  Find the work done (in J) by the force of gravity.

A cord is used to vertically lower an initially stationary block of mass M = 4.9 kg at a constant downward acceleration of g/7. When the block has fallen a distance d = 2.4 m, find (a) the work done by the cord's force on the block, (b) the work done by the gravitational force on the block, (c) the kinetic energy of the block, and (d) the speed of the block. (Note : Take the downward direction positive) (a) Number Units (b) Number Units (c) Number Units (d) Number Units

A 5.40-kg block is set into motion up an inclined plane with an initial speed of v; = 8.20 m/s (see figure below). The block comes to rest after traveling d = 3.00 m along the plane, which is inclined at an angle of 0 = 30.0° to the horizontal. (a) For this motion, determine the change in the block's kinetic energy. J (b) For this motion, determine the change in potential energy of the block-Earth system. J (c) Determine the friction force exerted on the block (assumed to be constant). N (d) What is the coefficient of kinetic friction?

A 5.80-kg block is set into motion up an inclined plane with an initial speed of v₁ = 8.20 m/s (see figure below). The block comes to rest after traveling d = 3.00 m along the plane, which is inclined at an angle of 0 = to the horizontal. V. (a) For this motion, determine the change in the block's kinetic energy. (b) For this motion, determine the change in potential energy of the block-Earth system. (c) Determine the friction force exerted on the block (assumed to be constant). N (d) What is the coefficient of kinetic friction?

A small boat is crossing a pond on a windy day. During some interval of time, the boat undergoes the given displacement Ar: Ař = (3.50 m)i + (2.85 m)ĵ During the same interval of time, the wind exerts the given force F on the boat: F = (260 N) – (135 N)Ĵ (a) What is the total work done on the boat by the wind over this period of time? (b) What is the angle between the direction of the wind force and the direction of the boat's motion during this time interval?