Exam 4: Forces and Newtons Laws of Motion

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?

You are standing in a moving bus, facing forward, when you suddenly slide forward as the bus comes to an immediate stop. What force caused you to slide forward?

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

A block is on a frictionless table, on earth. The block accelerates at 5.3 m/ $\mathrm { s } ^ { 2 }$ when a $10 \mathrm {~N}$ 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/ $\mathrm { s } ^ { 2 }$ . A horizontal force of 5 N is now applied to the block when it is on the Moon. The acceleration imparted to the block by this force is closest to

A box is placed on a table which rests on the floor. The box pushes on the table; the reaction force to the box's push on the table is the table's push on the floor.

A 1200-kg car is pulling a 500-kg trailer along level ground. Friction of the road on the trailer is negligible. The car accelerates with an acceleration of 1.3 m/s². What is the force exerted by the car on the trailer?

In order to get an object moving, you must push harder on it than it pushes back on you.

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?

The figure shows two boxes, with m₁ > m₂, that are on a level frictionless surface. We can apply a horizontal force $\overrightarrow { \mathbf { F } }$ either toward the right on m₁ or toward the left on m₂. The magnitude of the force that the boxes exert on each other is

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).

While flying horizontally in an airplane, you notice that a string dangling from the overhead luggage compartment hangs at rest at 15° away from the vertical toward the front of the plane. Using this observation, you can conclude that the airplane is

A block is on a frictionless table, on earth. The block accelerates at 3.0 m/ $\mathrm { s } ^ { 2 }$ when a $20 \mathrm {~N}$ 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/ $\mathrm { s } ^ { 2 }$ . The weight of the block on the Moon is closest to

During a hard stop, a car and its passengers slow down with an acceleration of 8.0 m/s². What magnitude force does a 50-kg passenger exert on the seat belt in such a stop?

A person who normally weighs 700 N is riding in an elevator that is moving upward but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read?

A golf club hits a golf ball with a force of 2400 N, sending the ball into the air. The force exerted on the club by the ball must be less than 2400 N or else the ball would not have moved forward.

A car of mass 1100 kg that is traveling at 27 m/s starts to slow down and comes to a complete stop in 578 m. What is the magnitude of the average braking force acting on the car?

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.)

If you pound a feather with a hammer, which one feels a greater force?

A horse pulls a cart with force $\overrightarrow { \mathbf { F } }$ . As a result of this force the cart accelerates with constant acceleration. The magnitude of the force that the cart exerts on the horse

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?