Question 1

A catcher stops a 0.15-kg ball traveling at 40 m/s in a distance of 20 cm. What is the magnitude of the average force that the ball exerts against his glove?

Accepted Answer

The answer of A catcher stops a 0.15-kg ball traveling...

Question 2

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

Accepted Answer

A)  equal to the weight of the bucket. 
B)  greater than the weight of the bucket. 
C)  less than the weight of the bucket. 
A)  equal to the weight of the bucket. 
B)  greater than the weight of the bucket. 
C)  less than the weight of the bucket.

Question 3

A flatbed truck is carrying an 800-kg load of timber that is not tied down. The maximum friction force between the truck bed and the load is 2400 N. What is the greatest acceleration that the truck can have without losing its load?

Accepted Answer

The answer of A flatbed truck is carrying an 800-kg...

Question 4

You are in a train traveling on a horizontal track and notice that a piece of luggage starts to slide directly toward the front of the train. From this observation, you can conclude that this train is

Accepted Answer

A)  speeding up. 
B)  slowing down. 
C)  changing direction. 
D)  speeding up and changing direction. 
E)  slowing down and changing direction. 
A)  speeding up. 
B)  slowing down. 
C)  changing direction. 
D)  speeding up and changing direction. 
E)  slowing down and changing direction.

Question 5

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?

Accepted Answer

A)  0.27 m/s2 
B)  1.1 m/s2 
C)  2.6 m/s2 
D)  11 m/s2 
A)  0.27 m/s2 
B)  1.1 m/s2 
C)  2.6 m/s2 
D)  11 m/s2

Question 6

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.

Accepted Answer

A) True 
 B)False

Question 7

A 75-N box rests on a perfectly smooth horizontal surface. The minimum force need to start the box moving is

Accepted Answer

A)  75 N. 
B)  7.5 N. 
C)  750 N. 
D)  any horizontal force greater than zero. 
A)  75 N. 
B)  7.5 N. 
C)  750 N. 
D)  any horizontal force greater than zero.

Question 8

A 590-kg rocket is at rest on the launch pad. What upward thrust force is needed to accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

Accepted Answer

The answer of A 590-kg rocket is at rest on...

Question 9

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?

Accepted Answer

Question 10

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).

Accepted Answer

A)  1.8 × 104 N 
B)  1.6 × 104 N 
C)  5.4 × 104 N 
D)  6.5 × 105 N 
E)  3.2 × 104 N 
A)  1.8 × 104 N 
B)  1.6 × 104 N 
C)  5.4 × 104 N 
D)  6.5 × 105 N 
E)  3.2 × 104 N

Question 11

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g = 9.80 m/s2?

Accepted Answer

A)  69.9 kg 
B)  68.5 kg 
C)  71.3 kg 
D)  72.7 kg 
A)  69.9 kg 
B)  68.5 kg 
C)  71.3 kg 
D)  72.7 kg

Question 12

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

Accepted Answer

A)  A constant force is being applied to it in the direction of motion. 
B)  A constant force is being applied to it in the direction opposite of motion. 
C)  A constant force is being applied to it perpendicular to the direction of motion. 
D)  The net force on the object is zero. 
E)  Its acceleration is in the same direction as it velocity. 
A)  A constant force is being applied to it in the direction of motion. 
B)  A constant force is being applied to it in the direction opposite of motion. 
C)  A constant force is being applied to it perpendicular to the direction of motion. 
D)  The net force on the object is zero. 
E)  Its acceleration is in the same direction as it velocity.

Question 13

The figure shows an object's acceleration-versus-force graph. What is the mass of this object?

Accepted Answer

A)  2.5 g 
B)  1.6 g 
C)  630 g 
D)  400,000 g 
A)  2.5 g 
B)  1.6 g 
C)  630 g 
D)  400,000 g

Question 14

You pull on a crate with a rope. If the crate moves, the rope's pull on the crate must have been larger than the crate's pull on the rope, but if the crate does not move, both of these pulls must have been equal.

Accepted Answer

A) True 
 B)False

Question 15

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

Accepted Answer

A)  moving forward. 
B)  moving backward. 
C)  accelerating forward. 
D)  accelerating backward. 
E)  not accelerating because the string is at rest. 
A)  moving forward. 
B)  moving backward. 
C)  accelerating forward. 
D)  accelerating backward. 
E)  not accelerating because the string is at rest.

Question 16

In a collision between a huge SUV and a small hybrid car, the SUV exerts a larger force on the hybrid than the hybrid exerts on the SUV.

Accepted Answer

A)  True 
B)  False 
C)  It depends on whether the collision is a head-on collision or a rear-end collision. 
A)  True 
B)  False 
C)  It depends on whether the collision is a head-on collision or a rear-end collision.

Question 17

A 958-N rocket is coming in for a vertical landing. It starts with a downward speed of 25 m/s and must reduce its speed to 0 m/s in 8.0 s for the final landing.
(a) During this landing maneuver, what must be the thrust due to the rocket's engines?
(b) What must be the direction of the engine thrust force?

Accepted Answer

(a) 1300 N

Question 18

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?

Accepted Answer

A)  550 N 
B)  600 N 
C)  650 N 
D)  700 N 
E)  750 N 
A)  550 N 
B)  600 N 
C)  650 N 
D)  700 N 
E)  750 N

Question 19

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

Accepted Answer

A)  always the feather 
B)  always the hammer 
C)  The size of the force is always exactly the same on both of them. 
D)  If the feather moves, then it felt the greater force. Otherwise the force was the same on both. 
A)  always the feather 
B)  always the hammer 
C)  The size of the force is always exactly the same on both of them. 
D)  If the feather moves, then it felt the greater force. Otherwise the force was the same on both.

Question 20

What magnitude net force is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s?

Accepted Answer

A)  444 N 
B)  1620 N 
C)  3240 N 
D)  4360 N 
E)  11800 N 
A)  444 N 
B)  1620 N 
C)  3240 N 
D)  4360 N 
E)  11800 N

Exam 4: Forces and Newtons Laws of Motion

A catcher stops a 0.15-kg ball traveling at 40 m/s in a distance of 20 cm. What is the magnitude of the average force that the ball exerts against his glove?

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

A flatbed truck is carrying an 800-kg load of timber that is not tied down. The maximum friction force between the truck bed and the load is 2400 N. What is the greatest acceleration that the truck can have without losing its load?

You are in a train traveling on a horizontal track and notice that a piece of luggage starts to slide directly toward the front of the train. From this observation, you can conclude that this train is

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?

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 75-N box rests on a perfectly smooth horizontal surface. The minimum force need to start the box moving is

A 590-kg rocket is at rest on the launch pad. What upward thrust force is needed to accelerate the rocket uniformly to an upward speed of 28 m/s in 3.3 s?

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?

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).

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g = 9.80 m/s2?

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

The figure shows an object's acceleration-versus-force graph. What is the mass of this object?

You pull on a crate with a rope. If the crate moves, the rope's pull on the crate must have been larger than the crate's pull on the rope, but if the crate does not move, both of these pulls must have been equal.

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

In a collision between a huge SUV and a small hybrid car, the SUV exerts a larger force on the hybrid than the hybrid exerts on the SUV.

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?

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

What magnitude net force is required to accelerate a 1200-kg car uniformly from 0 m/s to 27.0 m/s in 10.0 s?

Representing Motion

Motion in One Dimension

Vectors and Motion in Two Dimensions

Applying Newtons Laws

Gravity

Rotational Motion

Equilibrium Ad Elasticity

Momentum

Energy and Work

Using Energy

Thermal Properties of Matter

Fluids

Oscillations

Traveling Waves and Sound

Superposition and Standing Waves

Wave Optics

Ray Optics

Optical Instruments

Electric Fields and Forces

Electric Potential

Current and Resistance

Circuits

Magnetic Fields and Forces

EM Induction and Em Waves

AC Electricity

Relativity

Quantum Physics

Atoms and Molecules

Nuclear Physics

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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?

What is the mass of an object that experiences a gravitational force of 685 N near Earth's surface where g = 9.80 m/s²?

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?