**12. A 1200-kg car is being driven up a 5.0° hill. The frictional force is directed opposite to the motion of the car and has a magnitude of f = 524 N. A force F is applied to the car by the road and propels the car forward. In addition to these two forces, two other forces act on the car: its weight W and the normal force Fy directed perpendicular to the road surface. The length of the road up the hill is 290 m. What should be the magnitude of F, so that the net work done by all the forces acting on the car is +150 kJ?

A 35.0-kg child swings in a swing supported by two chains, each 2.98 m long. The tension in each chain at the lowest point is 440 N. (a) Find the child's speed at the lowest point.m/s(b) Find the force exerted by the seat on the child at the lowest point. (Ignore the mass of the seat.)N (upward)

A 19.0 kg box is placed at the top of an inclined plane and released to either move freely or sit at rest. The plane is at an angle of 30° above the ground and has a total length of d = 2.80 m along the incline. The coefficient of static friction between the box and the plane is us = 0.40 and the coefficient of kinetic friction is pk = 0.30. What kind of friction does the box experience once it is released, and what is its magnitude? m d Kinetic, Fkf - 55.9 N Static, Fsf = 74.5 N Static, Fsf = 64.5 N Kinetic, Fkf = 48.4 N

a person is pushing a 50 kg block across the ground at a constant speed of 10m/s with a force of 100 N, using a lever inclined angle of 20 degrees. What is the normal force on the box?

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A 756 N person travels in his vehicle through a deep circular-shaped dip in the road. When the vehicle passes through the lowest point of the 50.0 m dip, the seat exerts an 1110 N force on the person. Determine the speed of the vehicle at this point.

What is the acceleration of a car that maintains a constant velocity of 55 m/s for 10 seconds. a. 0 m/ s2 b. 0.55 m/ s2 c. 550 m/ s2 d. 5.5 m/ s2