Exam 5: Applying Newtons Laws

Newton's second law: The following four forces act on a 4.00 kg object: ₁ = 300 N east ₂ = 700 N north ₃ = 500 N west ₄ = 600 N south What is the acceleration of the object?

Multiple-object systems without friction: Two bodies P and Q on a smooth horizontal surface are connected by a light cord. The mass of P is greater than that of Q. A horizontal force (of magnitude F) is applied to Q as shown in the figure, accelerating the bodies to the right. The magnitude of the force exerted by the connecting cord on body P will be

General questions: A fish weighing 16 N is weighed using two spring scales, each of negligible weight, as shown in the figure. What will be the readings of the scales?

General questions: A dog is standing in the bed of a pickup truck. The bed is coated with ice, causing the force of friction between the dog and the truck to be zero. The truck is initially at rest, and then accelerates to the right, moving along a flat road. As seen from a stationary observer (watching the truck move to the right), the dog

Multiple-object systems with friction: A system comprised blocks, a light frictionless pulley, and connecting ropes is shown in the figure. The 9.0-kg block is on a perfectly smooth horizontal table. The surfaces of the 12-kg block are rough, with μ_k = 0.30 between it and the 9-kg block. If the 5.0-kg block accelerates downward when it is released, find its acceleration.

Slanted surfaces with friction: A 4.00-kg block rests on a 30.0° incline as shown in the figure. If the coefficient of static friction between the block and the incline is 0.700, what magnitude horizontal force F must act on the block to start it moving up the incline?

Slanted surfaces with friction: The figure shows two packages that start sliding down a 20° ramp from rest a distance along the ramp from the bottom. Package A has a mass of 5.0 kg and a coefficient of kinetic friction 0.20 between it and the ramp. Package B has a mass of 10 kg and a coefficient of kinetic friction 0.15 between it and the ramp. How long does it take package A to reach the bottom?

Uniform circular motion: A car drives over a hilltop that has a radius of curvature 0.120 km at the top of the hill. At what speed would the car be traveling if its tires just barely lose contact with the road when the car is at the top of the hill?

Friction: A pickup truck is moving at 25 m/s with a toolbox of mass m resting on the bed of the truck 2.5 m behind the cab. Suddenly the brakes are applied, causing the toolbox to slide, and the truck comes to a stop in 4.7 s. The coefficient of kinetic friction between the toolbox and the bed of the truck is 0.28. After the brakes are applied, how much time elapses before the toolbox strikes the cab?

Newton's second law: The International Space Station has a mass of 1.8 × 10⁵ kg. A 70.0-kg astronaut inside the station pushes off one wall of the station so she accelerates at 1.50 m/s². What is the magnitude of the acceleration of the space station as the astronaut is pushing off the wall? Give your answer relative to an observer who is space walking and therefore does not accelerate with the space station due to the push.

Multiple-object systems without friction: A wooden block A of mass 4.0 kg slides on a frictionless table when pulled using a massless string and pulley array by a hanging box B of mass 5.0 kg, as shown in the figure. What is the acceleration of block A as it slides on the frictionless table? Hint: Think carefully about the acceleration constraint.

Newton's second law: In a ballistics test, a 1.50-g bullet is fired through a 28.0-kg block traveling horizontally toward the bullet. In this test, the bullet takes 11.4 ms to pass through the block as it reverses the block's velocity from 1.75 m/s to the right to 1.20 m/s to the left with constant acceleration. Find the magnitude of the force that the bullet exerts on the block during this ballistics test.

Newton's second law: A 1000-kg car is driving toward the north along a straight horizontal road at a speed of 20.0 m/s. The driver applies the brakes and the car comes to a rest uniformly in a distance of 200 m. What are the magnitude and direction of the net force applied to the car to bring it to rest?

Uniform circular motion: A car enters a 300-m radius horizontal curve on a rainy day when the coefficient of static friction between its tires and the road is 0.600. What is the maximum speed at which the car can travel around this curve without sliding?

Newton's second law: On a horizontal frictionless floor, a worker of weight 0.900 kN pushes horizontally with a force of 0.200 kN on a box weighing 1.80 kN. As a result of this push, which statement could be true?

Uniform circular motion: A Ferris wheel has diameter of 10 m and makes one revolution in 8.0 seconds. A person weighing 670 N is sitting on one of the benches attached at the rim of the wheel. What is the apparent weight (that is, the normal force exerted on her by the bench) of the person as she passes through the highest point of her motion?

Newton's second law: If a 5.0 kg box is pulled simultaneously by a 10.0 N force and a 5.0 N force, then its acceleration must be

Newton's second law: A 10,000-kg rocket blasts off from earth with a uniform upward acceleration of 2.00 m/s² and feels no air resistance. The upward thrust force its engines must provide during this acceleration is closest to

Slanted surfaces without friction: A box slides down a frictionless plane inclined at an angle θ above the horizontal. The gravitational force on the box is directed

Newton's second law: A block is on a frictionless horizontal table, on earth. This block accelerates at 3.6 m/ when a horizontal force is applied to it. The block and table are then set up on the moon where the acceleration due to gravity is 1.62 m/ . A horizontal force of 45 N is applied to the block when it is on the moon. What acceleration does this force impart to the block?