Exam 4: Dynamics: Newtons Laws of Motion

A 150-N crate is being pulled up a perfectly smooth ramp that slopes upward at by a pull that is directed at above the surface of the ramp. What is the magnitude of the pull required to make the crate move up the ramp at a constant velocity of 1.75 m/s?

An object that weighs 75 N is pulled on a horizontal surface by a horizontal pull of 50 N to the right. The friction force on this object is 30 N to the left. What is the acceleration of the object?

If a net force accelerates a 4.5-kg tool at 40 m/s², what acceleration would that same net force give to an 18-kg tool?

A 200-N sled of slides down a frictionless hillside that rises at 37° above the horizontal. What is the magnitude of the force that the hill exerts on the sled parallel to the surface of the hill?

A person is using a rope to lower a 5.0-N bucket into a well with a constant speed of 2.0 m/s. What is the magnitude of the force exerted by the rope on the bucket?

An object has a mass of 60 kg on Earth. What are the mass and weight of this object on the surface of the Moon where the acceleration due to gravity is only 1/6 of what it is on Earth?

Two boxes, A and B , are connected by a horizontal string S on a horizontal floor. A very light wire pulls horizontally on box B, as shown in the figure, with a force of 100 N. The reaction force to this pull is

Jason takes off across level water on his jet-powered skis. The combined mass of Jason and his skis is 75 kg (the mass of the fuel is negligible). The skis produce a forward thrust of 200 N and have a Coefficient of kinetic friction with water of 0.10. Unfortunately, the skis run out of fuel after only 90 S) What is Jason's top speed?

Calculate the average force a bumper would have to exert to bring a 1200-kg car to rest in 15 cm when the car had an initial speed of 2.0 m/s (about 4.5 mph).

A push of magnitude P acts on a box of weight W as shown in the figure. The push is directed at an angle $\theta$ below the horizontal, and the box remains a rest. The box rests on a horizontal surface that has some friction with the box. The friction force on the box due to the floor is equal to

A piano mover raises a 1000-N piano at a constant speed using a very light rope in a frictionless pulley system, as shown in the figure. With what force is the mover pulling down on the rope?

A locomotive is pulling three train cars along a level track with a force of 100,000 N. The car next to the locomotive has a mass of 80,000 kg, the next one, 50,000 kg, and the last one, 70,000 kg. You can neglect the friction on the cars being pulled. (a) What is the magnitude of the force between that the 80,000-kg car exerts on the 50,000-kg car? (b) What is the magnitude of the force that the 50,000-kg car exerts on the 70,000-kg car?

A bucket is being lowered by a very light rope with a constant downward velocity. The tension in the rope must be

As shown in the figure, a woman is straining to lift a large crate, but without success because it is too heavy. We denote the forces on the crate as follows: P is the magnitude of the upward force Being exerted on the crate by the person, C is the magnitude of the vertical contact force on the Crate by the floor, and W is the weight of the crate. How are the magnitudes of these forces related While the person is trying unsuccessfully to lift the crate?

A block is on a frictionless table, on earth. The block accelerates at 3.0 m/s² when a 20 N horizontal force is applied to it. The block and table are set up on the Moon where the acceleration due to Gravity is 1.62 m/s². The weight of the block on the Moon is closest to

When a 45-kg person steps on a scale in an elevator, the scale reads a steady 480 N. Which of the following statements must be true? (There could be more than one correct choice.)

An object is moving with constant non-zero velocity. Which of the following statements about it must be true?

A satellite is in orbit around the earth. Which one feels the greater force?

An object of mass m rests on a flat table. The earth pulls on this object with a force of magnitude mg . What is the reaction force to this pull?

A 50.0-kg crate is being pulled along a horizontal smooth surface. The pulling force is 10.0 N and is directed above the horizontal. What is the magnitude of the acceleration of the crate?