Question 1

A split highway has a number of lanes for traffic. For traffic going in one direction, the radius for the inside of the curve is half the radius for the outside. One car, car A, travels on the inside while another car of equal mass, car B, travels at equal speed on the outside of the curve. Which statement about resultant forces on the cars is correct?

Accepted Answer

A) The force on A is half the force on B. 
B) The force on B is half the force on A. 
C) The force on A is four times the force on B. 
D) The force on B is four times the force on A. 
E) There is no net resultant force on either as long as they stay on the road while turning.

Question 2

Two small cylindrical plastic containers with flat bottoms are placed on a turntable that has a smooth flat surface. Canister A is empty; canister B contains lead shot. Each canister is the same distance r from the center. The coefficient of static friction between the canisters and the turntable is μs. When the speed of the turntable is gradually increased,

Accepted Answer

A) only the lighter container slides outward off the turntable; the heavier one stays on. 
B) only the heavier container slides outward off the turntable; the lighter one stays on. 
C) both containers slide off the turntable at the same turntable speed. 
D) the lighter container slides inward. 
E) the heavier container slides inward.

Question 3

The first of two identical boxes of mass m is sitting on level ground. The second box is sitting on a ramp that makes an angle with the ground. When a force of magnitude F is applied to each box in a direction parallel to the surface it is on, upwards on the box on the ramp, neither box moves. Which statement comparing the friction force on the box on the level, Fs,L, to the friction force on the box on the ramp, Fs,R, is correct?

Accepted Answer

A) Fs,R = Fs,L. 
B) Fs,R > Fs,L. 
C) Fs,R <Fs,L. 
D) The coefficient of static friction is needed to determine the correct answer. 
E) Depending on the values of the coefficient of static friction, the angle of elevation of the ramp, the mass of the boxes, and the applied force, answers (a), (b), and (c) are each a possible correct answer.

Question 4

A car enters a level, unbanked semi-circular hairpin turn of 100-m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is μ = 0.800. If the car maintains a constant speed of 28 m/s, it will

Accepted Answer

A) attempt to dig into the road surface. 
B) tend to veer toward the center of the semicircle. 
C) arrive safely at the end of the semicircle. 
D) tend to veer toward the outside of the circle. 
E) veer toward the center for the first quarter-circle, then veer toward the outside for the second quarter-circle.

Question 5

A space station in the form of a large wheel, 120 m in diameter, rotates to provide an "artificial gravity" of 3.00 m/s² for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.

Accepted Answer

The answer of A space station in the form of...

Question 6

A 0.30-kg mass attached to the end of a string swings in a vertical circle (R = 1.6 m), as shown. At an instant when θ = 50°, the tension in the string is 8.0 N. What is the magnitude of the resultant force on the mass at this instant?

Accepted Answer

A) 5.6 N 
B) 6.0 N 
C) 6.5 N 
D) 5.1 N 
E) 2.2 N

Question 7

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air

Accepted Answer

A) it must be increasing its speed. 
B) it must exert a force on the air that is directed to the plane's left side. 
C) it must exert a force on the air that is directed to the plane's right side. 
D) it does not need to exert a force: it must only move the wing flaps out. 
E) it only needs to deflect the air without exerting any additional force on the air.

Question 8

An amusement ride consists of a car moving in a vertical circle on the end of a rigid boom. The radius of the circle is 10 m. The combined weight of the car and riders is 5.0 kN. At the top of the circle the car has a speed of 5.0 m/s which is not changing at that instant. What is the force of the boom on the car at the top of the circle?

Accepted Answer

A) 3.7 kN down 
B) 1.3 kN down 
C) 6.3 kN up 
D) 3.7 kN up 
E) 5.2 kN down

Question 9

A roller-coaster car has a mass of 500 kg when fully loaded with passengers. At the bottom of a circular dip of radius 40 m (as shown in the figure) the car has a speed of 16 m/s. What is the magnitude of the force of the track on the car at the bottom of the dip?

Accepted Answer

A) 3.2 kN 
B) 8.1 kN 
C) 4.9 kN 
D) 1.7 kN 
E) 5.3 kN

Question 10

When a car goes around a circular curve on a level road without slipping,

Accepted Answer

A) no frictional force is needed because the car simply follows the road. 
B) the frictional force of the road on the car increases when the car's speed decreases. 
C) the frictional force of the road on the car increases when the car's speed increases. 
D) the frictional force of the road on the car increases when the car moves to the outside of the curve. 
E) there is no net frictional force because the road and the car exert equal and opposite forces on each other.

Question 11

An airplane travels 80 m/s as it makes a horizontal circular turn which has a 0.80-km radius. What is the magnitude of the resultant force on the 75-kg pilot of this airplane?

Accepted Answer

A) 0.69 kN 
B) 0.63 kN 
C) 0.66 kN 
D) 0.60 kN 
E) 0.57 kN

Question 12

A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?

Accepted Answer

A) The race car will crash into the outer wall. 
B) The race car will crash into the inner wall. 
C) The car will stay in the center of the track. 
D) The car will stay in the center of the track if the driver speeds up. 
E) The car would stay in the center of the track if the radius were reduced to 200 m.

Question 13

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 500-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

Accepted Answer

A) 0.25 
B) 0.50 
C) 1.00 
D) 2.00 
E) 4.00

Question 14

If a dense 20.0-kg object is falling in air at half its terminal velocity, what is the drag force on the object at this moment?

Accepted Answer

A) 24.5 N 
B) 49.0 N 
C) 69.3 N 
D) 98.0 N 
E) 139 N

Question 15

A sample of blood is placed into a centrifuge of radius 15.0 cm. The mass of a red corpuscle is 3.0 × 10−16 kg, and the centripetal force required to make it settle out of the plasma is 4.0 × 10−11 N. At how many revolutions per second should the centrifuge be operated?

Accepted Answer

The answer of A sample of blood is placed into...

Question 16

The following equation was obtained by solving a physics problem:  The best physical representation of the situation is

Accepted Answer

A) A car traveling at 16.0 m/s is 19.2° into a turn of a quarter circle on a level road. 
B) A mass on a string that is originally horizontal has fallen to where the angle between the string and the vertical direction is 19.2°. 
C) A mass on a string originally horizontal has fallen 19.2° from the horizontal direction. 
D) A car traveling at 16.0 m/s is on a circular curve banked at 19.2°. 
E) A car traveling at 16.0 m/s and going over a semicircular mountain-top road is 19.2° down from the top.

Question 17

The equation below is the solution to a problem. ​  .
​
The best physical representation of this equation is

Accepted Answer

A) a sphere of 2.00-kg mass under a 45.2-N tension when at the bottom of a vertical circle. 
B) a sphere of 2.00-kg mass under a 45.2-N tension when at the side of a vertical circle. 
C) a sphere of 2.00-kg mass under a 45.2-N tension when at the top of a vertical circle. 
D) a sphere of 2.00-kg mass at any point on a horizontal circle. 
E) a 2.00-kg gecko running on the ceiling with a speed of 8.00 m/s.

Question 18

A rock attached to a string swings in a vertical circle. Which free-body diagram could correctly describe the force(s) on the rock when it is at the lowest point, where  is the normal force,  is weight, and  is tension?

Accepted Answer

A)   
B)   
C)   
D)   
E)

Question 19

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 1000-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

Accepted Answer

A) 0.25 
B) 0.50 
C) 1.00 
D) 2.00 
E) 4.00

Question 20

The coefficient of static friction for the tires of a race car is 0.950 and the coefficient of kinetic friction is 0.800. The car is on a level circular track of 50.0 m radius on a planet where  compared to Earth's  . If the car is to be able to travel at the same speed on the planet as on Earth, the radius of the track on the planet must be ____ times as large as the radius of the track on Earth.

Accepted Answer

A) 0.250 
B) 0.500 
C) 1.00 
D) 2.00 
E) 4.00

Exam 6: Applications of Newtons Laws of Motion

A car enters a level, unbanked semi-circular hairpin turn of 100-m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is μ = 0.800. If the car maintains a constant speed of 28 m/s, it will

A space station in the form of a large wheel, 120 m in diameter, rotates to provide an "artificial gravity" of 3.00 m/s² for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.

A 0.30-kg mass attached to the end of a string swings in a vertical circle (R = 1.6 m) , as shown. At an instant when θ = 50°, the tension in the string is 8.0 N. What is the magnitude of the resultant force on the mass at this instant?

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air

A roller-coaster car has a mass of 500 kg when fully loaded with passengers. At the bottom of a circular dip of radius 40 m (as shown in the figure) the car has a speed of 16 m/s. What is the magnitude of the force of the track on the car at the bottom of the dip?

When a car goes around a circular curve on a level road without slipping,

An airplane travels 80 m/s as it makes a horizontal circular turn which has a 0.80-km radius. What is the magnitude of the resultant force on the 75-kg pilot of this airplane?

A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 500-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

If a dense 20.0-kg object is falling in air at half its terminal velocity, what is the drag force on the object at this moment?

A sample of blood is placed into a centrifuge of radius 15.0 cm. The mass of a red corpuscle is 3.0 × 10−16 kg, and the centripetal force required to make it settle out of the plasma is 4.0 × 10−11 N. At how many revolutions per second should the centrifuge be operated?

The following equation was obtained by solving a physics problem: The best physical representation of the situation is

The equation below is the solution to a problem. . The best physical representation of this equation is

A rock attached to a string swings in a vertical circle. Which free-body diagram could correctly describe the force(s) on the rock when it is at the lowest point, where is the normal force, is weight, and is tension?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 1000-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

Exam 6: Applications of Newtons Laws of Motion

A car enters a level, unbanked semi-circular hairpin turn of 100-m radius at a speed of 28 m/s. The coefficient of friction between the tires and the road is μ = 0.800. If the car maintains a constant speed of 28 m/s, it will

A space station in the form of a large wheel, 120 m in diameter, rotates to provide an "artificial gravity" of 3.00 m/s2 for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.

A 0.30-kg mass attached to the end of a string swings in a vertical circle (R = 1.6 m) , as shown. At an instant when θ = 50°, the tension in the string is 8.0 N. What is the magnitude of the resultant force on the mass at this instant?

For a plane to be able to fly clockwise in a horizontal circle as seen from above, in addition to exerting a force downwards on the air

A roller-coaster car has a mass of 500 kg when fully loaded with passengers. At the bottom of a circular dip of radius 40 m (as shown in the figure) the car has a speed of 16 m/s. What is the magnitude of the force of the track on the car at the bottom of the dip?

When a car goes around a circular curve on a level road without slipping,

An airplane travels 80 m/s as it makes a horizontal circular turn which has a 0.80-km radius. What is the magnitude of the resultant force on the 75-kg pilot of this airplane?

A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 500-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

If a dense 20.0-kg object is falling in air at half its terminal velocity, what is the drag force on the object at this moment?

A sample of blood is placed into a centrifuge of radius 15.0 cm. The mass of a red corpuscle is 3.0 × 10−16 kg, and the centripetal force required to make it settle out of the plasma is 4.0 × 10−11 N. At how many revolutions per second should the centrifuge be operated?

The following equation was obtained by solving a physics problem: The best physical representation of the situation is

The equation below is the solution to a problem. ​ . ​ The best physical representation of this equation is

A rock attached to a string swings in a vertical circle. Which free-body diagram could correctly describe the force(s) on the rock when it is at the lowest point, where is the normal force, is weight, and is tension?

An airplane flies in a horizontal circle of radius 500 m at a speed of 150 m/s. If the plane were to fly in the same 1000-m circle at a speed of 300 m/s, by what factor would its centripetal acceleration change?

A space station in the form of a large wheel, 120 m in diameter, rotates to provide an "artificial gravity" of 3.00 m/s² for persons located at the outer rim. Find the rotational frequency of the wheel (in revolutions per minute) that will produce this effect.

The equation below is the solution to a problem. . The best physical representation of this equation is