PHYSICS FINAL

A single force acts on an object. The components of this force act along the +x-axis and the -y-axis. The single force that will bring the object into equilibrium has components that act along the

-x-axis and +y-axis

During a three-part circus stunt a clown holds a ball. The clown then tosses the ball upward. After releasing it, the ball is caught a few moments later from above by another clown on a trapeze. Which set of data could represent the normal force exerted by the ground on the first clown during the stunt? The force due to gravity on the clown is 680 N and that on the ball is 20 N.,

700 N, 705 N, 680 N

Which of the following is not a form of mechanical energy?

Chemical potential energy

Sequences the steps in drawing a free-body diagram.

Draw a box Connect the tail of the arrow to the middle of the object Depending on the problem, extend the arrow in the direction the force is going Label the type of force and how many Newtons (if stated)

Units that measure weight are units of

Force

The tendency of an object to resist being moved is known as

Inertia

Which of the following is evidence that frictional forces are present in a system?

Interactions in the system cause an increase in temperature Interactions in the system produce sound Mechanical energy is conserved

A joule is equivalent to a

N x M

Which of Newton's Laws explained that Forces always exist in pairs?

Newton's First Law

A parachutist falls at a constant speed for 200 m. Which of the following is true?

No net work is done on the parachutist

A batter strikes a baseball with a bat. Identify an action-reaction pair and describe the forces exerted by each

The batter exerts a force on the bat; the bat exerts a force on the batter

If the sign of work is negative

The component of the force that does work is in the direction opposite the displacement

If a machine decreases the distance over which work is done

The force the machine applies is greater

Friction does -400 J of net work on a moving car. how does this affect the kinetic energy of the car?

The kinetic energy decreases by 400 J

The work-kinetic energy theorem states that

The net work done on an object equals the change in the kinetic energy of the object

In interactions of action-reaction pairs involving Earth and everyday objects the effect on Earth's motion is often negligible because,

the effect on Earth's motion is often negligible because, Earth has great inertia

An object is at rest on an incline. The component of gravity acting downward and along the incline on the object is described as F = +8.0N. Which axis is pointing up the incline?

x-axis

The gravitational force exerted on an object would most likely be represented by which force vector?

↓

A soccer ball kicked with a force of 18.6 N accelerates at 0.0065 km/s^2 to the left. What is the mass of the ball?

2.86 kg

In which of the following situations is mechanical energy most likely to be conserved?

A football flies through the air

Which of the following situations describes inertia?

A stationary object tends to resist being moved A moving object tends to resist a change in speed A moving object tends to resist a change in direction

In which of the following cases is no work done?

A weightlifter holds a barbell overhead

Energy associated with a compressed or stretched object is

Elastic potential energy

An action exerted on an object which may change the object's state of rest or motion defines

Force

Energy stored in the gravitational field of interacting bodies is

Gravitational potential energy

Energy that is due to the motion of an object is

Kinetic energy

Distinguish between mass and weight.

Mass is the amount of matter in an an object while weight is the amount of force in an object

A tennis ball is thrown up into the air starting from a height of 1.5 m. The ball reaches a peak height then falls down to the ground. Assuming air resistance is negligible, describe the energy transfers that take place during the flight of the ball. Is mechanical energy conserved in this situation?,

Mechanical energy is conserved because air resistance (friction) is negligible. When the ball is getting ready to be thrown, it is in gravitational potential energy. It transfers to kinetic energy once it is thrown into the air and while it comes back down

Which of the following refers to the rate at which energy is transferred?

Power

Which of the following refers to the rate at which work is done?

Power

How are power time, and energy related?,

Power is the time it takes for energy to be transferred in any method

Which has more kinetic energy a 4.0 kg bowling ball moving at 1.0 m/s or a 1.0 kg bocce ball moving at 4.0 m/s? Explain your answer.,

The bocce ball has more kinetic energy because the ball's smaller mass makes it lighter and is able to move at a higher velocity

How does the kinetic energy of an object change if the object's speed doubles?

The kinetic energy increases by a factor of 4

While sitting in a lounge chair with the back inclined at an angle of 10 degrees from the vertical you tuck a pillow between your head and the chair. Then you lower the chair back to 40 degrees and doze with the pillow in place. How has the net force on the pillow changed?

The net force is zero because the pillow stays in place

Which of the following statements describe an object in equilibrium?

The object is moving at constant velocity The net external force on the object is zero

The mechanical energy of a system of objects is

The sum of kinetic energy and all relevant forms of potential energy

As an object falls toward Earth

The upward acceleration of Earth is negligible because of its large mass

Which of the following is true of the conservation of energy in a closed system?

Total energy is always conserved

What is the SI unit for power?

W

Explain how action-reaction pairs keep a book sitting on a table in equilibrium

When a book is placed on a table, it exerts a force downwards on the table. That table then exerts an equal and opposite force on the book, keeping it in equilibrium.

Work is done on an object

Whenever a force causes a displacement of the object

In an action-reaction pair

the, Action force and the reaction force act on two different objects

A single force acting on an object is represented in a free-body diagram of the object by the following force vector: ↑. Which of the following force vectors represents a single force acting on the object that will bring the object into equilibrium?

↓

An egg suspended above the ground has 2.0 J of gravitational potential energy. The egg is then dropped and falls to the ground. What is the kinetic energy of the egg just as it reaches the ground?

2.0 J

A force of 5 N and a force of 15 N acting on an object can produce the following net forces except

5 N

A force unit is defined as the product of a mass unit and a unit of

Acceleration

Which of the following sentences uses work in the scientific sense?

An engine does work on a car when the car is moving

Two forces act on an object. The magnitude of the net force acting on the object

Cannot be determined from the given information

A 100 W light bulb

Converts 100 J of electrical energy to other forms of energy each second

A student holds a 6-N block of wood from a spring balance in an express elevator that maintains constant velocity traveling between floors. A spring scale reading of 5.9 N indicates that the elevator is

Ending an ascending trip

Which of the following statements are true about the concept of field forces?

Field forces can be exerted by objects that are in physical contact Field forces can be exerted by objects that are not in contact There are four fundamental field forces

Which of the following statements describe free-body diagrams?

Force diagrams show force vectors as arrows Forces exerted on the object are represented

Which of the following statements describe force diagrams?

Force diagrams show force vectors as arrows Forces exerted on the object are represented Forces exerted by the object are represented

Mechanical energy is not conserved when

Friction is not negligible

Which of the following is true of inertia?

It is described in Newton's first law of motion

If mechanical energy is conserved in a system the energy at any point in time can be in the form of,

Kinetic energy Elastic potential energy Gravitational potential energy

Two dogs are tugging on a toy. One dog pulls with a horizontal force of 14 N due north. The other is pulling due east with a horizontal force of 14 N. What is the direction of the net external horizontal force on the toy?

Northeast

Two books are lying next to each other on a library table. The force due to gravity on the first book is 9 N and on the second is 13 N. The gravitational force on the table itself is 125 N. The floor supports the table with an upward force of 147 N. In a free-body diagram of the table how many contact forces and how many field forces should be represented?

ONE contact force, THREE FIELD FORCES

In which situation is the net force acting on a car zero?

The car maintains both its speed and direction

How does the elastic potential energy in a mass-spring system change if the displacement of the mass is doubled?

The elastic potential energy increases or decreases by a factor of 4

If the distance over which work is done is increased by a machine

The force needed to complete work is less

A painter lifts a bucket of paint carries it 5 m horizontally, then sets it back down . which of the following is true?,

The force of gravity does negative work when the worker lifts the bucket

A truck and a car uniformly accelerate from rest to a velocity of 3.0 m/s in equal time intervals. The truck is ten times as massive as the car. WHich of the following statements is correct?

The force on the truck is 10 times the force on the car

A construction worker lifts a heavy cinder block 1 m off the ground holds it in place for 3 s, then sets it back down in the same place. Describe the forces doing work on the block and the net work on the block throughout this action.,

While lifting the block, the worker does positive work on the block while gravity does negative work on the block. The net work while lifting the block is positive. When the worker is holding the block, no forces do work on the block and no net work is done on the block. While lowering the block, the worker does positive work while gravity does negative work on the block. The net work on the block while it is lowered is negative. The total net work on the block is zero because the net displacement is zero.

Which of the following does not affect gravitational potential energy?

an object's speed

A student holds a 4.0-N block of wood from a spring balance in an express elevator that maintains constant velocity traveling between floors. A spring scale reading of 3.0 N indicates that the elevator is

ending an ascending trip

The change in the horizontal velocity of a 12-kg scooter is +0.5 m/s. What is the net horizontal force acting on it?

greater than 0 N