Download Kinetic energy

NAME: ____________________________________
7th Grade Science
DATE: _____________
Mr. Vorstadt
MULTIPLE CHOICE
______ 1- A flowing stream of water is an example of?
(1) potential energy
(2) chemical energy
(3) kinetic energy
(4) nuclear energy
______ 2- Because of friction?
(1) energy is always conserved.
(3) all energy is lost.
______ 3- A moving bicycle has?
(1) nuclear energy
(3) potential energy
(2) some potential energy turns into heat
(4) energy is not lost.
(2) chemical energy
(4) kinetic energy.
______ 4-When a tennis player hits a ball, the tennis player?
(1) does work on the ball.
(2) gives the ball energy
(3) produces radiant energy (4) answers 1 and 2 are correct.
______ 5- What type of energy transformation is represented in the diagram below?
(1) sound energy to electric energy
(2) electric energy to sound energy
(3) sound energy to chemical energy
(4) chemical energy to sound energy
______ 6- What type of energy is contained in gasoline?
(1) sound
(2) potential (3) kinetic (4) mechanical
______ 7- Power is scientifically defined as the?
(1) ability to do work.
(2) rate at which work is done.
(3) energy of position.
(4) energy in motion.
______ 8- The best example of an object that possesses potential energy is?
(1) a falling rock
(2) a piece of coal (3) Mr. V falling
(4) a rolling rock
______ 9- As a skateboarder goes down a hill, some of the skateboarders energy is?
(1) kinetic
(2) potential
(3) electrical (4) answers 1 & 2 are correct.
_____ 10- An objects kinetic energy can be increased by increasing it's?
(1) speed (2) power
(3) mass (4) answers 1 & 3.
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_____ 11- In the diagram below, a skier is about to start a slide (position 1), ski down
the hill (2), and STOP at the bottom (3). At which position would the skier
have the most kinetic energy?
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(1) 1 (2) 2
(3) 3
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Hill
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Questions 12 and 13 refer to the following activity.
Angie stretches a large rubber band and then releases one of its ends. The rubber band snaps
back to its original shape.
_____ 12- As the rubber band was snapping back, it had
(1) no energy
(2) position energy
(3) potential energy
(4) kinetic energy
_____ 13- When the rubber band was stretched, it had
(1) kinetic energy (2) potential energy (3) motion energy (4) no energy
_____ 14- Power is measured in?
(1) Watts (2) Joules
(3) Newton-meters (4) grams
_____ 15- which item transforms 100% of the energy it receives into useful energy?
(1) hair dryer
(2) window fan
(3) none of the items.
(4) Battery-powered flashlight
Thinking and Analyzing
Questions 16 and 17 refer to the following activity. In an effort to break a strip of aluminum
metal, Charles bent it back and forth many times. He was surprised to notice the aluminum
getting warm at the point of the bend.
_____ 16. The heating of the metal strip in this case
(1) is the loss of energy
(3) is an unusable energy transformation
(2) is a gain of energy
(4) is the creation of energy
_____ 17. This is an example of a transformation of
(1) mechanical energy to heat energy
(2) chemical energy to heat energy
(3) heat energy to mechanical energy
(4) chemical energy to mechanical energy
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_________ 18- True or False. Kinetic energy is energy due to an objects position?
Questions 19-21 refer to the following diagram.
Lighting matches in a matchbook
illustrates several different
energy transformations
_____19- The burning match involves the transformation of
(1) heat energy to light energy, only
(2) chemical energy to light and sound energy
(3) chemical energy to light and heat energy
(4) chemical energy to heat energy, only
_____ 20- The matches in the matchbook contain
(1) potential chemical energy (2) potential light energy
(3) potential heat energy
(4) kinetic heat energy
_____21- When you strike a match on the rough strip of a matchbook cover, you
transform
(1) mechanical energy to heat energy
(2) mechanical energy to chemical energy
(3) mechanical energy to electric energy
(4) heat energy to chemical energy
_____ 22- Which sequence of energy transformations occurs after a battery-operated flashlight
is turned on?
(1) chemical → light → electrical
(2) chemical → electrical → light
(3) electrical → light → chemical
(4) electrical → chemical → light
_____ 23- Which statement best describes the energy changes that occur while a child is riding
on a sled down a steep, snow-covered hill?
(1) Kinetic energy increases and potential energy decreases.
(2) Kinetic energy decreases and potential energy increases.
(3) Both potential energy and kinetic energy increase.
(4) Both potential energy and kinetic energy decrease.
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_____ 24- The diagram below shows a boulder rolling down a hill into a valley and then up the
opposite hill.
At which position does the boulder have the greatest kinetic energy?
(1) A (2) B (3) C (4) D
_____ 25- The illustration below shows an example of energy changing forms.
Which changes in energy form are illustrated in the diagram?
(1) mechanical → light → sound and electrical
(2) light → electrical → mechanical and sound
(3) sound → mechanical → light and electrical
(4) electrical → sound → light and mechanical
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FORMULAS
Kinetic energy (KE) = ½ mv2
Potential energy (PE) = force x distance
Joules (J)
________ 26- A 20kg bicycle moving at 2 m/s has a KE of?
________ 27- If you push a 40kg wheelbarrow at 2m/s, the wheelbarrows KE is?
________ 28- If you push a 40kg cart at 2m/s, the carts KE is?
________ 29- A 10 N rock that is 12 meters above the ground has a PE of?
________ 30- A 20kg ball moving at 2m/s has a kinetic energy of?
________ 31- If a 200N rock is pushed up a 3 meter hill the rock's potential energy is?
Power = energy/time = Watts (W)
Work = power x time = Joules (J)
________ 32- A person who does 500 joule of work in 100 seconds has of power.
________ 33- If a person does 4,000 joules of work in 20 min, the person's power is?
________ 34- A toy that supplies 20 watts of power moves for 5 sec. has done of work.
________ 35- A light bulb that supplies 200 W of power for 10 sec has done of work.
DIAGRAMS: Use the diagrams below to complete questions 36-45.
36- If the bicycle's potential energy will be 2,000 J at point C,
the hill is ___________ high.
37- The bicycle's potential energy at point A is ___________.
C
38- At point B, some of the bicycles kinetic energy will be changed
to _____________________ .
39- If the bicycle is moving at point A, it's kinetic energy is
B
__________ then it's potential energy.
40- If the bicycle were stopped at point C, it's
kinetic energy would be __________ .
200N
A
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Potential energy- can also be stored by changing the shape of an object. Stretching a rubber
band or spring is a way to store potential energy. This energy is released when the object snaps
back to its original shape.
Directions For each question, write your answer in the spaces provided.
41. How is potential energy stored in an object? ______________________________________
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42. Which has greater kinetic energy, a car going 30 mph or one going 40 mph energy? Explain.
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43. Which has greater potential energy, a roller coaster at the top of a hill, or a roller coaster at
the bottom of a hill? Explain. ___________________________________________________
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Base your answers to questions 44 and 45 on the diagram of a moving car below and on your
knowledge of science. The diagram shows energy transformations.
_____ 44. What is the sequence of the energy
transformations represented in the
diagram? [1]
(1) solar → chemical → electrical
(2) mechanical → chemical → solar
(3) mechanical → electrical → solar
(4) solar → electrical → mechanical
45. State one advantage to the environment of using the car shown in the diagram instead of a
car powered by fossil fuel.
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