Physics MOP Question Bank

Which of the following are examples of work being done (either positive or negative) upon an object? Choose all that apply

- A rightward force is applied to an object to move it to the right at a constant speed - A rightward force is applied to an object to accelerate it to the right - An upward force is applied to a downward moving object to slow it down as it moves - An upward force is applied to an object to move it upward at a constant speed - An upward force is applied to an object to accelerate it upward

Which of the following variations will increase the potential energy of an object? Select all that apply

- Increase the object's mass - Increase the object's height

Which of the following variations will increase the kinetic energy of an object? Select all that apply

- Increase the object's speed - Increase the object's mass

Some forces are categorized as conservative forces (or internal forces) while others are categorized as non-conservative forces (or external forces). Which of the following forces are generally categorized as non-conservative (or external) forces? Choose all that apply

- Normal Force - Air Resistance Force - Applied Force - Force of Friction - Tension Force

A 5-Newton force is applied to a 2-kg object to move it across a horizontal surface at a constant speed for a distance of 4 meters. The free-body diagram is shown below. Which of the following forces are doing work upon the object - either positive or negative? Choose all that apply (square with 4 equal forces)

- applied force - friction force

Suppose that an object moves downward with a decreasing speed. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___.

- decrease - decrease - decrease

Suppose that an object slows down while moving horizontally. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___ .

- decrease - remains the same - decrease

Some forces are categorized as conservative forces (or internal forces) while others are categorized as non-conservative forces (or external forces). Which of the following forces are generally categorized as conservative (or internal) forces? Choose all that apply

- force of gravity - spring force

Suppose that an object moves upward with an increasing speed. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___.

- increase - increase - increase

Suppose that an object speeds up while moving horizontally. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___

- increase - remain the same - increase

An object will definitely have potential energy if it is _____. Select all that apply

- moving above the ground (a non-zero height) - at rest above the ground (a non-zero height)

An object will have kinetic energy if it is _____. Select all that apply

- moving above the ground (a non-zero height) - moving on the ground (height = 0 m) - moving

If the only forces doing work upon an object are conservative (or internal) forces, then the total mechanical energy of the object will ___. If the only forces doing work upon an object are non-conservative (or external) forces, then the total mechanical energy of the object will ___.

- not change - change - either increase or decrease

Suppose that an object moves downward at a constant speed. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___.

- remain the same - decrease - decrease

Suppose that an object moves upward at a constant speed. In this situation, the object's kinetic energy would ___ , its potential energy would ___ , and its total mechanical energy would ___.

- remain the same - increase - increase

Two objects of identical mass begin from rest at the same height at the top of two different hills - hill A and hill B. The hills are inclined at two different angles (see diagram). The objects are released from rest and slide to the bottom; resistance forces can be considered to be negligible. The object on top of hill ____ will have the smallest speed at the bottom of the incline.

... nonsense! Both objects will have identical speeds at the bottom

An object has a kinetic energy of 32 J. If the object's speed is doubled, then its new kinetic energy will be ____ J

128

A 60-kg mountain climber ascends (climbs) 15 meters up a steep cliff in 60 seconds. The power rating of the mountain climber is ____ W

150

A horizontal force of 80 Newton is applied to a 10-kg crate to move it horizontally a distance of 4 meters across a concrete floor at a constant speed of 2 m/s. The task requires 2 seconds. The power rating for the person applying the force is approximately _____ W

160

The kinetic energy and the potential energy of a roller coaster car at various locations are shown. The total mechanical energy of the car at position D is ____ Joules

330000

Jack and Jill are doing a physics lab. They apply a 30-Newton force to a 6-kg cart to pull it up an inclined plane at a constant speed. The plane is inclined at a 30-degree angle. Jack and Jill are exerting a force on the cart that is parallel to the inclined plane in order to displace it 2.0 meters along the incline to a final height of 1 meter. During this lab, the amount of work done on the cart is approximately ____ Joules

60

In a physics lab, a 60-kg student runs up a 2.0-meter tall flight of stairs in 1.5 seconds. The student's power rating is approximately _____ W

800

For the physical situation described below, select the appropriate work-energy bar chart. A baseball player moving with a speed of 8.5 m/s (initial state) dives head-first and slides to a stop (final state) along level ground.

A

Consider the three situations described below. In which situation(s) would the mechanical energy NOT be conserved? Choose all that apply.

A softball player slides into third base across the infield dirt.

A 60-kg parachutist falls with a constant velocity of 8 m/s from a height of 2000 meters (A) to a height of 500 meters (B). Use g = 10 m/s/s to perform an energy analysis and fill in all the blanks. (Enter a negative number if an answer is negative.)

At point A, KE= 1,920 J At point A, PE= 1,200,000 J. Between A and B, W = -900,000 At point B, KE= 1,920 J At point B, PE= 300,000 J.

An 800-kg car moving with a speed of 28 m/s (at A) puts on the brakes and slows down to a speed of 14 m/s (at B). Use g = 10 m/s/s to perform an energy analysis and fill in all the blanks. (Enter a negative number if an answer is negative.)

At point A, KE= 313,600 J At point A, PE= 0 J. Between A and B, W = -235,200 At point B, KE= 78,400 J At point B, PE= 0 J.

The path of a projectile moving through the air is shown in the diagram below. Frictional forces can be assumed to be negligible. Perform an energy analysis and answer the questions corresponding to the blanks in the diagram.

At point B, KE= 15 J At point C, KE= 4 J At point D, PE= 13 J At point E, KE= 22 J At point E, PE= 0 J

The path of a sledder gliding across the ice and snow is shown in the diagram below. Frictional forces can be assumed to be negligible. Perform an energy analysis and fill in all the blanks.

At point B, KE= 6000 J. At point C, KE= 11000 J At point D, PE= 2000 J. At point E, KE= 11000 J At point E, PE= 0 J.

Consider the work energy bar charts shown below. Select any bar chart that portrays a situation in which mechanical energy is NOT conserved.

B, D

The standard metric unit of work is the ____

Joule

Mac and Tosh run up the same hill. Mac has twice the mass as Tosh. Tosh climbs up the hill in one-half the time as Mac. In this situation,

Mac does more work than Tosh, but they have the same power rating

The standard metric unit of power is a

Watt

The essential difference between work and power is that power is

a rate quantity and work is not a rate quantity

If an object is moving above the ground (at a non-zero height), then it will not have any kinetic energy

false

In order to have work done upon an object, there must be a(n) ____ to cause a(n) ____

force acting upon the object, displacement

A 5-Newton friction force acts upon a 2-kg object to slow it down as it moves it across a horizontal surface over a distance of 4 meters. The free-body diagram is shown below. Which of the following forces are doing work upon the object - either positive or negative? Choose all that apply (square with equal normal, friction, and gravity, no applied)

friction force

Kinetic energy is the energy that an object possesses due to its ____ and potential energy is the energy that an object possesses due to its ____

motion, position

A softball player is sliding into third base. Once she hits the dirt, the force of friction acts upon her to slow her down as she slides a distance of 1.5 meters across the distance. In this example, friction is doing ____ work upon the player

negative

In order for an object to conserve its total mechanical energy it is absolutely necessary that ____.

non-conservative (i.e., external) forces do NOT do net work upon the object

A child is pushing an empty box across a living room floor. The child exerts a constant rightward force upon the box to move it a distance of 2 meters to the right. In this example, the child is doing ____ work upon the box

positive

Work is a ____ quantity; it is fully described by stating its ____

scalar, magnitude alone

Power is defined as

the rate at which work is done upon an object

The total mechanical energy of an object is ____

the sum of its kinetic energy and its potential energy

Student A and student B are doing two identical tasks involving physical work. Student A does the task in more time than student B. In this physical situation,

the two students do the same amount of work but student B has the greater power rating

The kinetic energy (KE) and potential energy (PE) values are shown for various locations. In this example, ____. Select all that apply

total mechanical energy is conserved

If non-conservative forces (i.e., external forces) are acting upon an object, then the total mechanical energy of that object could still remain constant.

true

Consider the types of forces present in the following physical situation: A bucket full of water is slowly lifted by a rope out of a deep well. In this situation, the total mechanical energy of the bucket of water ____.

will definitely change

Consider the types of forces present in the following physical situation: A car is skidding to a stop. In this situation, the total mechanical energy of the car ____.

will definitely change

Consider the types of forces present in the following physical situation: A parachutist is falling downward, encountering a large amount of air resistance. In this situation, the total mechanical energy of the parachutist ____.

will definitely change

If both conservative (i.e., internal) and non-conservative (i.e., external) forces are doing net work upon an object, then the total mechanical energy of the object ____.

will definitely change

Consider the types of forces present in the following physical situation: A dart is traveling through the air towards a dart board. Assume that air resistance is negligible. In this situation, the total mechanical energy of the dart ____.

will remain constant

Consider the types of forces present in the following physical situation: A roller coaster car is coasting down the first drop of the track. Assume that resistance forces have no effect on the car's motion. In this situation, the total mechanical energy of the car ____.

will remain constant

A man is walking through an airport with a suitcase. The man exerts a constant upward force upon the suitcase as he walks a distance of 20 meters. In this example, the man is doing ____ work upon the suitcase

zero