The universe’s total amount of energy does not ever change, but the amount of this energy that is available to do work varies tremendously. What statement best explains the changes in available energy?(1 point)
Responses
A. The only way to create energy is through nuclear reactions.
B. Energy constantly changes from one form to another.
C. Energy transfer always occurs through heat.
D. 100% of energy is always converted with perfect efficiency.
B. Energy constantly changes from one form to another.
When a match is struck, what forms of energy does the burning match give off?(1 point)
Responses
A. Light energy and thermal energy
B. Nuclear energy and light energy
C. Thermal energy and solar energy
D. Solar energy and nuclear energy
A. Light energy and thermal energy
When a match is struck, what forms of energy does the burning match give off?(1 point)
Responses
A. Light energy and thermal energy
B. Nuclear energy and light energy
C. Thermal energy and solar energy
D. Solar energy and nuclear energy
A. Light energy and thermal energy
When an electric fan is plugged into a wall outlet, the fan blades spin as a result. What energy transformation occurred?(1 point)
Responses
A. Electrical to mechanical
B. Mechanical energy is created, but electrical energy is destroyed.
C. Electrical energy is created, but mechanical energy is destroyed.
D. Mechanical to electrical
A. Electrical to mechanical
A simple circuit is wired with a battery, a switch, and a bell.
When the switch is turned on, what energy transformations will occur?
(1 point)
Responses
A. The battery’s chemical energy transforms to sound energy, which the wire transfers to the bell.
B. The switch’s electrical energy transforms to sound energy, which the wire transfers to the bell.
C. The switch transforms electrical energy to chemical energy, which the bell then transforms to sound energy.
D. The battery’s chemical energy transforms to electrical
B. The switch's electrical energy transforms to sound energy, which the wire transfers to the bell.
A woman runs as shown.
What main energy conversion occurs?
(1 point)
Responses
A. Chemical energy changes into mechanical energy because energy from digestion of food provides energy for the runner’s motion.
B. Mechanical energy changes into thermal energy because the energy from motion creates heat in the air around the runner.
C. Thermal energy changes into mechanical energy because heat provides energy for motion.
D. Mechanical energy changes into chemical energy as the kinetic energy from motion creates reactions in the surrounding air.
A. Chemical energy changes into mechanical energy because energy from digestion of food provides energy for the runner's motion.
Heated gases will rise to the top of its container. Why does this occur?(1 point)
Responses
A. Heated gases will increase in kinetic energy and decrease in density.
B. Heated gases will decrease in kinetic energy and decrease in density.
C. Heated gases will decrease in kinetic energy and increase in density.
D. Heated gases will increase in kinetic energy and increase in density.
A. Heated gases will increase in kinetic energy and decrease in density.
An ice cube is placed on a metal block that is at a room temperature of 30oC. Which statement describes the transfer of heat between the ice cube and metal block?(1 point)
Responses
A. Heat is transferred from the air to the ice cube, and the ice melts.
B. Heat is transferred from the air and metal to the ice cube, and the ice melts.
C. Heat is transferred from the ice cube to the metal block, and the ice melts.
D. Heat is transferred from the ice cube to the air, and the ice melts.
C. Heat is transferred from the ice cube to the metal block, and the ice melts.
Lucy is making a cup of hot chocolate. She puts the chocolate and hot water into a cup, and stirs the mixture.
A few minutes later, she notices the cup and the spoon have gotten hot. What made Lucy’s cup and spoon get hot?
(1 point)
Responses
A. Heat was transferred through conduction to the cup and spoon when the hot water molecules flowed in currents through the cooler molecules of the hot chocolate mix and transferred heat.
B. Heat was transferred through conduction to the cup and spoon when the hot water molecules collided frequently with the cooler molecules in the cup and spoon and transferred heat.
C. Heat was transferred through convection to the cup and spoon when the hot water molecules moved through the cooler molecules in the surrounding air and transferred heat.
D. Heat was transferred through convection to the cup and spoon when the hot water molecules radiated into the cooler molecules of the hot chocolate mix and transferred heat.
B. Heat was transferred through conduction to the cup and spoon when the hot water molecules collided frequently with the cooler molecules in the cup and spoon and transferred heat.
The picture below shows two flasks, one with hot water and one with room temperature water, which are connected by a conductive metal bar.
In which direction does the thermal energy between the flasks flow?
(1 point)
Responses
A. Thermal energy does not flow between the two flasks.
B. Thermal energy flows equally between the two flasks.
C. Thermal energy flows from the flask with room temperature water to the flask with hot water.
D. Thermal energy flows from the flask with hot water to the flask with room temperature water.