If a car generates 15.6 hp when traveling at a steady 96.1 km/hr, what must be the average force exerted on the car due to friction and air resistance. (1hp = 746 watts) %3D

4. A 4.7 kg block is pushed 3.1 m up a vertical wall with constant speed by a constant force of magnitude Fapplied at an angle 8=35° with the horizontal, as shown in the Figure. If the coefficient of kinetic friction between block and wall is 0.23, determine a) The work done by F, b) the work done by the force of gravity, c) the work done by the normal force between block and wall. d) By how much does the gravitational potential energy increase during the block's motion? F

A force of F= (263 N)E -(125 Nj acts on an objeut, causing a displacement of Āp =(3.15 m) î + (2.81 m) . %3D What is the work done on the object?

ry the system T Am 27. A 5000 kg dump truck has a maximum 400 hp (1 hp = 746 W), and it is moving up on an inclined road with a slope of 15 degrees. If the frictional coefficient on the road is 0.80, what is the max constant speed that the trucker can maintain on the inclined? FV FN fi FL trictional No motion. (0) FNA Force F is now even 6.1 (a) The forces on a Friction An external ntronger but is still 12

A 390 kg crate hangs from the end of a rope of length L = 12.0m. You push horizontally on the crate with a varying force F → to move it a horizontal distance d = 3.50 m to the side.  Find the work your force F →  does on the crate in Joules.

A 7.80-g bullet moving at 530 m/s penetrates a tree trunk to a depth of 4.50 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 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.

2. An ocean diver swims upwards against the drag force exerted by the water. This force varies in magnitude by depth (d) and is given by F(d)=√d, where y=100 N/m ¹/2. If the diver ascends from a depth of d=10m to the surface (d=0), what is the work done by this drag force? Why is this work negative?

A 1350-kg car is traveling with an initial speed of 25.0 m/s. Determine the car's speed after -2.20 × 10° J of net work is done on the car. X m/s

3. Suppose you have an object attached to a bizarre spring, initially located at x = 0, the equilibrium point of the force of the spring on the object is given by F₁ = kx, S where k is a spring constant. (a) You displace the object from x = 0 to ₁ > 0, holding the object steady at the beginning and end. What is the work done by the spring? What is the work done by you? (b) You let go of the spring and observe the object move from location. x₁ to x2. Is x2 less than or greater than ₁? (c) What is the kinetic energy of the object at x2? (d) Is this bizarre spring realistic? Explain.