A 40 kg crate is pulled across the ice with a rope. A force of 100 N, 30° is applied by the rope. Assume friction is negligible. (a) Determine the acceleration of the crate. (b) Determine the normal force that the crate exerts on the ice.

1. A block of mass 3.00-kg is pushed against a wall by a force P that makes an angle of 50.00 with the horizontal as shown in the figure below. The coefficient of static friction between the block and the wall is 0.250. Determine the possible values for the magnitude of P that allow the block to remain stationary.

3. A 180 g hockey puck slides on (frictionless) ice at a speed of 2 m/s. It then slides onto a carpet, which exerts a constant frictional force F₁ = 0.7 N in the direction opposite the puck's direction of motion. (a) Draw two free body diagrams: one when the puck is on the ice, and the other when the puck is on the carpet. Include any forces acting in the vertical direction (perpendicular to the ice or carpet) and any acting in the horizontal direction (parallel to the ice or carpet). (b) Do you expect the velocity of the puck to be constant on the ice? How about on the carpet? Why or why not? (c) How far does the puck travel on the carpet before coming to a stop?

3. A delivery person slides a 15-kg box of kitchen supplies from his truck using a metal slider. It was observed that the box slid at a constant velocity of 2 m/s. What is the coefficient of kinetic friction if the slider was inclined at an angle of 25°?

37. A suitcase with mass 18 kg is pulled at a constant speed by a handle that makes an angle θ with the horizontal. The frictional force on the suitcase is 27 N and the force applied on the handle is 43 N. (a) Determine the value of the angle, θ. (b) Determine the normal force exerted on the suitcase.

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31. A truck with mass 2000 kg tows a boat and trailer of total mass 500 kg. The frictional coefficient for the truck is 0.080 and for the trailer is 0.050 (this is due to “rolling resistance” of the tires). The force of the truck’s drive wheels pushing backward on the pavement is 3.0 kN. (a) Determine the acceleration rate of the truck and trailer moving forward together. (b) Determine the amount of force the truck’s hitch exerts forward on the trailer.

3. On a windy day, a quarterback throws a football into the wind. After the football has left the quarterback's hand and is moving through the air, the correct list of the force(s) acting on the football is ... a force from the throw and the downward force of gravity. a force from the throw, a force exerted by the air, and gravity. a) b) a force from the throw, and a force exerted by the air. a force exerted by the air, and the downward force of gravity. c)