Exam 5: Newtons Laws of Motion

A 777 aircraft has a mass of 300,000 kg. At a certain instant during its landing, its speed is 27.0 m/s. If the braking force is 445,000 N, what is the speed of the airplane 10.0 s later?

A student uses a plumb bob to verify that the doorjamb in a car is vertical. As the car pulls away from a stop, the student observes that the string now makes an angle θ with the doorjamb. Why does this happen?

The force you exert on Earth is insignificant compared to the force Earth exerts on you.

An object is being acted upon by three forces and moves with a constant velocity. One force is 60 N along the x-axis, the second is 75 N along the y-axis. What is the direction of the third force, measured counterclockwise from the x-axis?

A golf club hits a golf ball with a force of 2400 N. The golf ball hits the club with a force

FIGURE 5-3 -The three forces represented in Figure 5-3 act on an object. What is the direction of the acceleration of the object?

Three boxes rest side-by-side on a smooth, horizontal floor. Their masses are 5.0 kg, 3.0 kg, and 2.0 kg, with the 3.0-kg mass in the center. A force of 50 N pushes on the 2.0-kg mass, which pushes against the other two masses. What is the contact force between the 5.0-kg mass and the 3.0-kg mass?

A student pulls a box of books on a smooth horizontal floor with a force of 100 N in a direction of 37.0° above the horizontal. The mass of the box and the books is 40.0 kg. (a) Draw the free-body diagram for the box. (b) Calculate the acceleration of the box. (c) Calculate the normal force acting on the box.

A horse pulls a cart with force . As a result of this force the cart accelerates with constant acceleration. What is the magnitude of the force that the cart exerts on the horse?

A locomotive is pulling three wagons along a level track with a force of 100,000 N. The wagon next to the locomotive has a mass of 70,000 kg, the next one, 50,000 kg, and the last one, 80,000 kg. Neglect friction. What is the force between the 70,000-kg and 50,000-kg wagons?

You apply the same force to two objects. Object 1 has mass M and object 2 has mass 5M. The acceleration of object 2 is

FIGURE 5-1 -In Figure 5-1, masses m₁ and m₂ are such that m₁ > m₂ and they lay on a level, frictionless surface. We can apply a horizontal force either from the left or from the right. The contact force between masses m₁ and m₂ is

In the absence of an external force, a moving object will

A 3.0-kg and a 5.0-kg box rest side-by-side on a smooth, level floor. A horizontal force of 32 N is applied to the 5.0-kg box pushing it against the 3.0-kg box, and, as a result, both boxes slide along the floor. How large is the contact force between the two boxes?

A 40.0-kg crate is being raised by means of a rope. Its upward acceleration is 2.00 m/s². What is the force exerted by the rope on the crate?

The locking mechanism for the seatbelt of a car makes use of the fact that the apparent vertical direction (i.e. the direction in which a plumb bob hangs) changes with the car's deceleration. In a certain collision, the deceleration of a car is 5.00 g. What angle does the apparent vertical make with the true vertical?

A block of mass M slides down a frictionless plane inclined at an angle θ with the horizontal. The normal reaction force exerted by the plane on the block is directed

A student uses a plumb bob to verify that the doorjamb in a car is vertical. As the car pulls away from a stop, the student observes that the string now makes an angle θ with the doorjamb. What is the acceleration of the car?

What average net force is required to accelerate a car with a mass of 1200 kg from 0 to 27.0 m/s in 10.0 s?

A net force of 125 N is applied to a certain object. As a result, the object accelerates with an acceleration of 24.0 m/s². The mass of the object is