Forces, Energy and Work

Multiple Choice

The combination of all the forces acting on an object is the...

• net force
• action force
• reaction force
• balance force

Multiple Choice

Which of the following is the correct unit for measuring force?

• Joules

• Watts

• Newtons

• Meters per second

Multiple Choice

Which of the following is NOT one of the ten different forces commonly recognized by physicists?

• Applied

• Friction

• Elastic

• Drag

Open Ended

Explain how gravitational force affects objects on Earth and describe its significance in achieving flight or maintaining an orbit.

Multiple Choice

Force is a

• A push or a pull

• A force of attraction between objects that pulls objects towards each other.

• A force that works against motion between two surfaces that are in contact.

• A contact force of friction that opposes the motion of objects moving in the air.

Multiple Choice

Which force is directly responsible for causing motion in an object, as shown in the example of a person throwing a basketball?

• Friction force

• Applied force

• Normal force

• Gravitational force

Multiple Select

Select all statements that correctly describe friction based on the diagram and text.

• Friction acts in the same direction as an object's movement.

• The rougher the surface, the stronger the resisting force.

• Static friction prevents an object from moving.

• Kinetic friction acts on a moving object.

Multiple Choice

A force exerted by a compressed or stretched spring upon any object that is attached to it.

• Spring Force

• Tension Force

• Elastic Force

Open Ended

Explain how the density of an object compared to the density of a fluid determines whether the object will float or sink.

Multiple Select

Which of the following are true about magnetic fields?

• Magnetic field lines flow from the north pole to the south pole.

• Magnetic fields affect only metallic objects.

• Opposite poles repel each other.

• Magnets are responsible for frictionless transportation.

Open Ended

Summarize what you learned about forces in today's lesson. How do you think understanding forces can help you in real life?

Multiple Choice

Explain what happens to the potential energy of a rock as it falls off the side of a cliff.

• The kinetic energy decreases as the potential energy increases.
• The kinetic energy decreases as the potential energy decreases.
• The potential energy decreases as the kinetic energy increases.
• The potential energy decreases as the kinetic energy decreases. 

Multiple Select

The force of gravity increases as... (select two that apply)

• the mass of an object increases

• the mass of an object decreases

• the distance between two objects decreases (gets closer)

• the distance between two objects increases (gets furrther apart)

Multiple Choice

The sum of kinetic and potential energy is called...

• sum energy

• nonmechanical energy

• mechanical energy

• space energy

Multiple Choice

The ability to do work is called

• energy

• force

• power

• machine

Multiple Choice

The total amount of energy

• varies

• can cancel out to zero

• goes out into space

• remains constant

Multiple Choice

What is the effect of friction on the motion of objects?

• It speeds them up

• It slows them down

• It changes their direction

• It has no effect

Multiple Choice

Why is it harder for the boy in Image B to get down the hill?

• Motion
• Friction
• Work
• Displacement

Multiple Choice

A juggler is juggling four bean bags. When does each bean bag have the greatest potential energy with respect to the floor?

• just after it is thrown

• just before it is caught

• when it reaches its highest point

• when it is moving at its greatest speed

Multiple Choice

work is done when

• the object you apply a force on moves

• any force is applied to an object, regardless if it moves or not

• the force is zero

• the force and direction of motion are perpendicular

Multiple Choice

What is the unit of report for energy?

• Joules

• meters

• newtons

• grams

Multiple Choice

The equation for force is

• W= fd

• W= fN

• W=mv

• W=wh

Multiple Choice

What is the rate at which energy is converted?

• potential energy

• kinetic energy

• mechanical energy

• power

Multiple Choice

Which form of energy is involved in a pencil falling from a desk?

• kinetic

• nonmechanical

• gravitational potential

• elastic potential