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Energy Types
Potential Energy
Kinetic Energy
Random Energy
Review Concepts
100
This type of energy occurs constantly as molecules move inside of substances. It can be increased by friction between molecules.
What is thermal energy
100
A diver is standing at the edge of a platform, ready to drop into the water. What two factors affect the amount of potential energy of the diver?
What is the mass of the diver and the height above the surface of the water.
100
What two factors affect the kinetic energy of an object?
What is the object's mass and velocity (or speed.)
100
Energy is defined as the ________________
What is ability to do work
100
What is a description of a phenomena in the natural world which always happens the same way?
What is: a scientific law
200
This type of energy occurs as molecules of a substance compress then expand in a longitudinal wave.
What is sound energy
200
If a pulley raises a 10 kg box to a distance of 1 meter from the floor, how much Potential Energy has been given to the box?
What is 98 J of energy
200
2 bowling balls of the same mass are rolling simultaneously down the same bowling lane. The pink ball is moving with a velocity of 1 m/s while the green ball is moving with a velocity of 3 m/s. How will this affect their kinetic energies?
What is: The green ball will have a KE which is 9 times greater than the pink ball because in the KE equation, KE = 1/2 mv^2, velocity is squared and the green ball is moving 3 times faster than the pink ball.
200
The units of one kg m^2 per s^2 is the same as one ______
What is Joule
200
What part of an experiment's results are graphed on the vertical axis?
What is: the dependent variable
300
This type of energy is increased as a rubber band is twisted around a lever.
What is elastic potential energy
300
If a rubber band has a spring constant of 100.0 and has been stretched 5 cm, how much potential energy has it been given?
What is 0.125 J (Remember to convert from cm to m) Also acceptable would be 0.1 J if rounding for sig figs
300
If a hat is picked up from the floor, placed on a kid's head, the kid walks forward with the hat on, then the hat falls off, what change happened while the hat was on the kid's head?
What is: The kinetic energy of the hat changed while the kid walked forward. Its potential energy remained the same because it was at the same height.
300
A box at the top of an incline that has friction. The box slides to the bottom of the incline. What equation would show the relationship expressing conservation of energy in this situation?
What is: KE bottom = PE top - friction
300
What term means the difference between the ending position and the starting position?
What is displacement
400
This type of energy occurs when a dam in a river collects water then sends it over the spillway to the stream 30 meters below.
What is gravitational potential energy
400
What is the potential energy of a child in a swing, if the Kinetic Energy of the child in the swing at the lowest point is 965 Joules? (Assume that air resistance is negligent)
What is 965 Joules due to the conservation of energy.
400
A kid on a scooter produces 32,000 J of kinetic energy, but the scooter only moves forward with 26,000 J of kinetic energy. What has happened to the "lost" energy?
What is: 6,000 J of kinetic energy were converted to thermal energy due to friction.
400
When popcorn falls from the air popper into the bowl below, what type of energy transformation is taking place?
What is: The air gave the popcorn kernel potential energy when it lifted it off of the bottom of the popper. As the popped kernel fell into the bowl below, that potential energy was converted to kinetic energy.
400
How long will it take a car to go from a complete stop to 8.0 m/s if it is accelerating at a rate of 5.0 m/s/s
What is 1.6 seconds Start with a = v/t, switch around to t = v/a
500
This type of energy occurs in the bonds between atoms. Examples include energy stored in wood, food, or coal.
What is chemical energy
500
A pendulum is swinging back and forth through the air. Describe the pendulum's potential energy and kinetic energy at the highest point on each side of its swing.
What is the potential energy will be the greatest at the highest point and the kinetic energy will be the least (probably 0) at the highest point of its swing.
500
You are pushing your 25.5 kg little brother on a swing. At a point 1.5 meters above the ground, he has 750 J of Kinetic Energy. Calculate your little brother's velocity at this point.
What is 7.7 m/s
500
If we were to graph the kinetic energy of a bullet fired from a gun, it would start out at zero, go very high, then slowly curve to zero. If we were to graph the potential energy of a bullet fired from a gun, it would start out high, then curve down to zero. If we were to graph the thermal energy of a bullet fired from a gun, it would be 0 then go high,then drop suddenly back to zero. What would the graph of the total energy of this system look like?
What is: The total energy would be a high-straight line because energy of the total system is constant.
500
A 2000 kg delivery truck moving at a velocity of 10 m/s crashes into a parked car which has a mass of 500 kg. If the velocity of the car after the crash is 12 m/s, what is the velocity of the delivery truck after the crash?
What is 7 m/s. Remember that momentum is conserved: Momentum before the crash must equal momentum after the crash.