Question 1

A boy sits in a tire that is attached to a rope that passes over a pulley fastened to the ceiling and then passes back down to the boy's hands.The weight of the boy plus the tire is W.The force with which the boy must pull on the free end of the rope to support his weight in the tire is

Accepted Answer

A) (1/2)W 
B) W 
C) 2W 
D) (2/3)W 
E) (3/2)W

Question 2

A boy holds a bird in his hand.The reaction force to the weight of the bird is the force of the:

Accepted Answer

A) Earth on the bird. 
B) bird on the Earth. 
C) hand on the bird. 
D) bird on the hand. 
E) Earth on the hand.

Question 3

A force F produces an acceleration a on an object of mass m.A force 3F is exerted on a second object,and an acceleration 8a results.What is the mass of the second object?

Accepted Answer

A) 3m 
B) 9m 
C) 24m 
D) (3/8)m 
E) (8/3)m

Question 4

A fat cat,ever conscious of its weight,walks into an elevator and steps on a scale.The elevator begins to accelerate downward.While the elevator is accelerating,the scale reads

Accepted Answer

A) more than when the elevator is stationary. 
B) more than if the elevator were accelerating upward. 
C) less than when the elevator is stationary. 
D) a negative value. 
E) Insufficient information is given to answer correctly.

Question 5

A car is accelerating at a rate of 2.5 m/s2.A mass of 250 g is hanging from the ceiling on a string 1.2 m long.The angle that the string makes with the vertical is

Accepted Answer

A) 14.3º toward the back of the car. 
B) 76º toward the back of the car. 
C) 7º toward the front of the car. 
D) 14.3º toward the front of the car. 
E) 0º,or straight down.

Question 6

An object with a mass M = 250 g is on a plane inclined at 30º above the horizontal and is attached by a string to a mass m = 150 g.There is no friction and mass m hangs freely and is initially at rest.When mass m has descended a distance h = 10 cm,its speed will be

Accepted Answer

A) 35.0 cm/s 
B) 7.00 cm/s 
C) 140 cm/s 
D) 110 cm/s 
E) 70.0 cm/s

Question 7

A net force of 64 N acts on a mass of 16 kg.The resulting acceleration is

Accepted Answer

A) 16 m/s2  
B) 0.51 m/s2  
C) 64 m/s2  
D) 9.0 m/s2  
E) 4.0 m/s2

Question 8

A 44.5-N weight is hung on a spring scale,and the scale is hung on a string.The string is lowered at a rate such that the entire assembly has a downward acceleration of 4.90 m/s2.The scale reads

Accepted Answer

A) 0 N 
B) 22.2 N 
C) 44.5 N 
D) 66.7 N 
E) 71.2 N

Question 9

Two springs with different spring constants,k1 and k2,are connected as shown in the figure below. 
 A force F is applied to one end.The force exerted by the wall on the spring is (take + to the right)

Accepted Answer

A) 0 
B) -k1 $\Delta$x1 
C) -k2 $\Delta$x2 
D) F 
E) -F

Question 10

What is the weight of a 50-kg boy on the moon,where the acceleration due to gravity is 1.6 m/s2?

Accepted Answer

A) 80 N 
B) 100 N 
C) 490 N 
D) 50 N 
E) 80 lb

Question 11

A lamp of mass m hangs from a spring scale that is attached to the ceiling of an elevator.When the elevator is stopped at the fortieth floor,the scale reads mg.What does it read as the elevator slows down to stop at the forty-fifth floor?

Accepted Answer

A) more than mg 
B) less than mg 
C) mg 
D) zero 
E) One cannot tell without knowing how fast the elevator is stopping.

Question 12

Which of the following statements is true?

Accepted Answer

A) The mass of a body is a quantitative measure of its inertia. 
B) Mass is a vector quantity. 
C) The mass of a body is directly proportional to the acceleration it is experiencing. 
D) The unit of mass in the U.S.customary system is the newton. 
E) The mass of a body is inversely proportional to the resultant force acting on it.

Question 13

A girl walks on a level floor in a straight line in the +x direction.Her foot exerts a force on the floor.The direction of the reaction force by the floor on her foot is in

Accepted Answer

A) +x direction 
B) -x direction 
C) +y direction (vertically up) 
D) -y direction (vertically down) 
E) depends how fast she is walking

Question 14

A mass of 25 kg is acted on by two forces:  1 is 15 N due east,and  2 is 10 N due north.The acceleration of the mass is

Accepted Answer

A) 0.72 m/s2,56.3º north of east. 
B) 0.20 m/s2,due east. 
C) 0.72 m/s2,33.7º north of east. 
D) 1.0 m/s2,33.7º north of east. 
E) 0.20 m/s2,56.3º north of east.

Question 15

An 80-kg man on ice skates pushes a 40-kg boy,also on skates,with a force of 100 N.The force exerted by the boy on the man is

Accepted Answer

A) 200 N 
B) 100 N 
C) 50 N 
D) 40 N 
E) zero unless the boy pushes back

Question 16

Of the following values,which is most nearly equal to the weight of a 1-kg body?

Accepted Answer

A) 1 N 
B) 103 dynes 
C) 2.2 lb 
D) 0.454 lb 
E) 2.2 N

Question 17

You are going up in an elevator that is accelerating upwards on Earth.Suppose you were to do the same thing on Mars.Your weight on Mars will be ___ your weight on Earth.

Accepted Answer

A) less than 
B) equal to 
C) greater than 
D) unable to tell 
E) depends on what g is on Mars

Question 18

The concept of a field

Accepted Answer

A) provides us with a way to understand how a body's presence is known over great distances. 
B) is a useful alternative to action at a distance for explaining gravitational forces. 
C) is that of space distorted by the presence of an object. 
D) is useful in describing electromagnetic interactions as well as gravitational interactions. 
E) is described by all of these.

Question 19

Three forces F1,F2 and F3 act on an object.If F1 = 3N i + 5N j + 7N k,F2 = -5N i - 2N j -2N k,and the object is moving at constant velocity then the vector force F3 is

Accepted Answer

A) -2N i - 3N j - 5N k 
B) 2N i - 3N j - 5N k 
C) 2N i + 3N j - 5N k 
D) -8N i - 7N j - 9N k 
E) 8N i + 7 N j +9N k

Question 20

Three forces,  ,  ,and  ,act on a mass of 4.2 kg.The forces are  The direction of the net acceleration

Accepted Answer

A) cannot be determined because the acceleration is zero. 
B) is 60º north of east. 
C) is 70º north of east. 
D) is 51º north of east. 
E) is 44º north of east.

Exam 4: Newtons Laws

A boy sits in a tire that is attached to a rope that passes over a pulley fastened to the ceiling and then passes back down to the boy's hands.The weight of the boy plus the tire is W.The force with which the boy must pull on the free end of the rope to support his weight in the tire is

A boy holds a bird in his hand.The reaction force to the weight of the bird is the force of the:

A force F produces an acceleration a on an object of mass m.A force 3F is exerted on a second object,and an acceleration 8a results.What is the mass of the second object?

A fat cat,ever conscious of its weight,walks into an elevator and steps on a scale.The elevator begins to accelerate downward.While the elevator is accelerating,the scale reads

A car is accelerating at a rate of 2.5 m/s².A mass of 250 g is hanging from the ceiling on a string 1.2 m long.The angle that the string makes with the vertical is

An object with a mass M = 250 g is on a plane inclined at 30º above the horizontal and is attached by a string to a mass m = 150 g.There is no friction and mass m hangs freely and is initially at rest.When mass m has descended a distance h = 10 cm,its speed will be

A net force of 64 N acts on a mass of 16 kg.The resulting acceleration is

A 44.5-N weight is hung on a spring scale,and the scale is hung on a string.The string is lowered at a rate such that the entire assembly has a downward acceleration of 4.90 m/s².The scale reads

What is the weight of a 50-kg boy on the moon,where the acceleration due to gravity is 1.6 m/s²?

A lamp of mass m hangs from a spring scale that is attached to the ceiling of an elevator.When the elevator is stopped at the fortieth floor,the scale reads mg.What does it read as the elevator slows down to stop at the forty-fifth floor?

Which of the following statements is true?

A girl walks on a level floor in a straight line in the +x direction.Her foot exerts a force on the floor.The direction of the reaction force by the floor on her foot is in

A mass of 25 kg is acted on by two forces: ₁ is 15 N due east,and ₂ is 10 N due north.The acceleration of the mass is

An 80-kg man on ice skates pushes a 40-kg boy,also on skates,with a force of 100 N.The force exerted by the boy on the man is

Of the following values,which is most nearly equal to the weight of a 1-kg body?

You are going up in an elevator that is accelerating upwards on Earth.Suppose you were to do the same thing on Mars.Your weight on Mars will be ___ your weight on Earth.

The concept of a field

Three forces F₁,F₂ and F₃act on an object.If F₁ = 3N i + 5N j + 7N k,F₂ = -5N i - 2N j -2N k,and the object is moving at constant velocity then the vector force F₃ is

Three forces, , ,and ,act on a mass of 4.2 kg.The forces are The direction of the net acceleration

Exam 4: Newtons Laws

A boy sits in a tire that is attached to a rope that passes over a pulley fastened to the ceiling and then passes back down to the boy's hands.The weight of the boy plus the tire is W.The force with which the boy must pull on the free end of the rope to support his weight in the tire is

A boy holds a bird in his hand.The reaction force to the weight of the bird is the force of the:

A force F produces an acceleration a on an object of mass m.A force 3F is exerted on a second object,and an acceleration 8a results.What is the mass of the second object?

A fat cat,ever conscious of its weight,walks into an elevator and steps on a scale.The elevator begins to accelerate downward.While the elevator is accelerating,the scale reads

A car is accelerating at a rate of 2.5 m/s2.A mass of 250 g is hanging from the ceiling on a string 1.2 m long.The angle that the string makes with the vertical is

An object with a mass M = 250 g is on a plane inclined at 30º above the horizontal and is attached by a string to a mass m = 150 g.There is no friction and mass m hangs freely and is initially at rest.When mass m has descended a distance h = 10 cm,its speed will be

A net force of 64 N acts on a mass of 16 kg.The resulting acceleration is

A 44.5-N weight is hung on a spring scale,and the scale is hung on a string.The string is lowered at a rate such that the entire assembly has a downward acceleration of 4.90 m/s2.The scale reads

Two springs with different spring constants,k1 and k2,are connected as shown in the figure below. A force F is applied to one end.The force exerted by the wall on the spring is (take + to the right)

What is the weight of a 50-kg boy on the moon,where the acceleration due to gravity is 1.6 m/s2?

A lamp of mass m hangs from a spring scale that is attached to the ceiling of an elevator.When the elevator is stopped at the fortieth floor,the scale reads mg.What does it read as the elevator slows down to stop at the forty-fifth floor?

Which of the following statements is true?

A girl walks on a level floor in a straight line in the +x direction.Her foot exerts a force on the floor.The direction of the reaction force by the floor on her foot is in

A mass of 25 kg is acted on by two forces: 1 is 15 N due east,and 2 is 10 N due north.The acceleration of the mass is

An 80-kg man on ice skates pushes a 40-kg boy,also on skates,with a force of 100 N.The force exerted by the boy on the man is

Of the following values,which is most nearly equal to the weight of a 1-kg body?

You are going up in an elevator that is accelerating upwards on Earth.Suppose you were to do the same thing on Mars.Your weight on Mars will be ___ your weight on Earth.

The concept of a field

Three forces F1,F2 and F3 act on an object.If F1 = 3N i + 5N j + 7N k,F2 = -5N i - 2N j -2N k,and the object is moving at constant velocity then the vector force F3 is

Three forces, , ,and ,act on a mass of 4.2 kg.The forces are The direction of the net acceleration

A car is accelerating at a rate of 2.5 m/s².A mass of 250 g is hanging from the ceiling on a string 1.2 m long.The angle that the string makes with the vertical is

A 44.5-N weight is hung on a spring scale,and the scale is hung on a string.The string is lowered at a rate such that the entire assembly has a downward acceleration of 4.90 m/s².The scale reads

What is the weight of a 50-kg boy on the moon,where the acceleration due to gravity is 1.6 m/s²?

A mass of 25 kg is acted on by two forces: ₁ is 15 N due east,and ₂ is 10 N due north.The acceleration of the mass is

Three forces F₁,F₂ and F₃act on an object.If F₁ = 3N i + 5N j + 7N k,F₂ = -5N i - 2N j -2N k,and the object is moving at constant velocity then the vector force F₃ is