Energy, Force, and Motion

Gina is driving her car down the street. She has a teddy bear sitting on the back seat. A dog runs in front of Gina's car, so she quickly applies the brakes. The force of the brakes causes the car to stop, but the teddy bear continues to move forward until it hits the car's dashboard.
The teddy bear did not stop at the same time as the car because 

• only objects touching the Earth's surface can be acted upon by an outside force.
• more force is required to stop softer objects than to stop harder objects.
• objects in motion tend to stay in motion unless acted upon by an outside force.
• objects in motion can only be stopped by the application of a balanced force.

Which of the following sequences correctly displays the energy transformation from the inside of a battery to the igniter inside a car's engine? 

• Electrical > Chemical > Heat
• Chemical > Electrical > Heat
• Chemical > Mechanical > Heat
• Heat > Electrical  > Chemical

A golf ball is dropped off of the side of a building. Ignore the effects of air resistance. As the ball continues to fall freely, the kinetic energy of the ball 

• increases
• decreases
• remains the same.
• equals zero.

An object's gravitational potential energy is partly dependent on its acceleration due to gravity (9.8 ^m/_s² near Earth's surface). What two other factors determine the object's gravitational potential energy? 

• mass and distance away
• time and mass
• speed and height
• kinetic energy and speed

Which of the following is a form of energy?
I. kinetic
II. thermal
III. potential
IV. electrical

• I and III only
• I, II, III, and IV
• IV only
• I, II, and III only

Tamara pours hot tea into a cold mug. A few moments later, she picks up the mug, and the mug is now warm.
What is the main form of energy transfer involved in heating the mug? 

• radiation
• conduction
• convection
• all of these

Melissa has a beaker of water. She adds heat energy to the water by placing the beaker over the flame of a Bunsen burner.
What happens to the motion of the water particles as Melissa adds heat energy to the water? 

• The water particles move faster.
• The water particles move slower.
• The motion of the water particles does not change.
• The water particles stop moving.

Thermal energy is transferred as heat from a warmer object to a cooler object until 

• all of the energy from the cold object is transferred to the hot object.
• the temperature is the same in both objects.
• the thermal energy is converted into another type of energy such as light.
• all of the energy from the hot object is transferred to the cold object.

Where do plants get energy to make food?

• air
• soil
• water
• sunlight

a force that causes a change in motion of an object

• friction
• balanced force
• unbalanced force
• force