Conservation of Energy

Which statement is true according to the law of conservation of energy?

• energy is never created or destroyed, it is only changed from one state to another.

• energy can not change from one state to another

• all energy can be either created or destroyed

• energy can not be conserved

What kind of energy transformation takes place in hydroelectric power plants?

• Chemical energy transforms to electrical energy

• Light energy transforms to mechanical energy

• Mechanical energy transforms to electrical energy

• Electrical energy transforms to chemical energy

A scientist is working to design a bouncy ball that conserves all of its kinetic and potential energy. He drops the ball to the ground from a height of 3 meters. If it really works, how high should the ball bounce?

• Between 4-5 meters

• Exactly 3 meters

• The ball will not bounce at all.

• Between 1-2 meters

What happens to the kinetic energy of a hot drink when an ice cube is put into the drink?

• Some of the kinetic energy of the drink is transferred to the ice cube.

• The total energy of the drink and ice cube decreases.

• The kinetic energy of the drink increases.

• The kinetic energy of the drink remains the same.

What does the term “conservation” mean in regards to energy?

• Energy is a fixed amount and once it is used it is lost forever.

• Energy can be created, but it cannot be destroyed.

• Energy is unstable and constantly changes from one form to another.

• Energy is not created or destroyed; the same amount is always present in some form.

A parked car begins to move when the driver presses the accelerator. How is energy conserved in this situation?

• The energy of momentum is destroyed.

• The energy in the car’s fuel is converted into kinetic energy.

• Energy is not conserved in this situation because the car moves faster.

• The car creates kinetic energy from nothing.

A student is holding a stone at a certain height. The stone has 50 joules of potential energy and 0 joules of kinetic energy. The stone is released from that height. How much energy does the stone have right before it hits the ground?

• The stone will have no energy.

• The stone will have about 50 joules of kinetic energy and 0 joules of potential energy.

• The stone will have about 50 joules of potential energy and 0 joules of kinetic energy.

• The stone will have about 25 joules each of kinetic and potential energy.

When Joel kicked a soccer ball, the ball gained energy and Joel lost energy. The amount of energy the soccer ball gained is _____________ the amount of energy that Joel lost.

• more than

• less than

• equal to

• Not enough information

Which statement best describes the relationship between the desired temperature increase of a substance and how much heat energy is needed?

• The greater the desired temperature increase, the more energy is needed.

• The amount of heat energy needed is the same regardless of the desired final temperature.

• This relationship is different for each type of material.

• The greater the desired temperature increase, the less energy is needed.

Which statement best describes the relationship between the mass of a substance and how much energy is needed to raise the substance’s temperature?

• The greater the mass of the substance, the more energy is needed to raise its temperature.

• There is no significant relationship between mass and energy needed to raise temperature.

• The greater the mass of the substance, the less energy is needed to raise its temperature.

• This relationship is different for each type of material.