Energy
A solar panel is capable of absorbing 750J of light energy every second, and converting 150J of that energy into electrical energy. What is the efficiency of this solar panel?
0.2 (20%)
A man expends 100 J of work to move a box up an inclined plane. The amount of work produced is 70J. What is the efficiency?
0.7
A machine has an input of 500 J of energy and an output of 400 J of energy. What is its efficiency?
0.8
Mario (60 kg) has a potential energy of 480 Joules when he jumps to hit a block. How high off the ground does he jump?
0.8 m
An object is dropped from rest at a height of 10 m. At what height is the potential energy of the object closest to 0? ________
0m
An object is dropped from rest at a height of 10 m. At what height is the kinetic energy of the object closest to 0?
10 m
A certain light bulb consumes 200J of electrical energy per second, but only emits 25J of light energy per second. Calculate the efficiency of this bulb.
12.5% (0.125)
A machine with an efficiency of 0.75 (75%) has an input energy of 160 J. What is the output energy?
120 J
If 300 Joules of work are done to move an object 20 m, how much force was applied?
15 N
If 80 Joules of work are done when 4 N of force are applied, what distance must the object have moved?
20 m
Rex the puppet has a mass of 5 kg. Jade throws it 3 m/s. What is the kinetic energy?
22.5 J
A giant gummy bear has a mass of 3 kg. When it is raised 8 m, how much potential energy does the giant gummy bear have?
240J
9 Newtons of force are applied to a crate, moving it 30 m. How much work is done on the crate?
270J
A 5 kg object starts at a height of 3 m off the ground. It is then lifted to a height of 9 m off the ground. What is its change in potential energy?
300J
Link attacks Pikachu (6 kg) sending him from the ground and into the air to a height of 5 m. What is his change in potential energy?
300J
A sled at rest at the top of a hill has 350 J of potential energy. Assuming no loss of energy to external forces or heat, what is the kinetic energy at the bottom of the hill? ___________
350 J
An 850 kg roller-coaster is released from rest at 140 m. Assume there is no friction or air resistance. What is the kinetic energy of the roller-coaster at 95 m?
382,500J
Pickle Rick has a potential energy of 320 Joules when he is 8 m off the ground. What is his mass?
4 kg
Eleven uses her mind to throw a 20,000 kg train car, giving it 160,000 Joules of kinetic energy. How fast is the train car?
4 m/s
A 25 kg object has 450 J of kinetic energy. What is its velocity?
6 m/s
A 12 kg object is lifted to a height of 5 m. How much work is done?
600J
A 5 kg bowling ball is dropped from the top of a building. If it hits the ground with a speed of 37.0 m/s, how tall was the building?
68.45 m
Which takes more work to lift: a 5 kg object lifted 10 m, or a 7 kg object lifted 8 m?
7 kg object
70 J of work are done on a box being lifted. What is the change in potential energy?
70 J
Spiderman (70 kg) shoots his web and swings from it. When his speed is 1.5 m/s, what is his kinetic energy?
78.75 J
A pulley system operates with 40% efficiency. If the work put in is 200 joules, how much useful work is produced?
80J
If 9,000 Joules of work are done to lift an object, how much potential energy has the object gained?
9,000 J
Why can't perpetual motion machines (machines that generate their own energy) exist?
Energy cannot be created
The formula for kinetic energy is __________________
KE=1/2 mv^2
Ms. Schramm pushes on a wall with a force of 20 N on the wall for 10 seconds. How much work does she do on the wall? Explain
No work, the wall doesn't move
The formula for potential energy is ____________
PE=mgh
What does it mean for energy to be conserved?
The total stays the same bc energy is neither created nor destroyed.
The formula for work is __________
W=Fd
The energy that holds molecules together and is found in food and batteries is called _______ energy
chemical
The formula for efficiency is __________
eff=Eout/Ein
The energy due to moving electrons creating current in a wire is called _________
electrical
Potential energy is the energy of a(n) _____________ object.
elevated
The energy of motion is called __________
kinetic
Kinetic energy is the energy of a _____________ object
moving
The energy that holds the nucleus of an atom together is called
nuclear
The stored energy due to position is called ________
potential
When speed doubles, kinetic energy
quadruples
Light, X-Rays, and other forms of electromagnetic radiation are types of ___________ energy
radiant
When an object vibrates back and forth, ______ energy is produced. It travels as a wave.
sound
The energy on a molecular level that affects an object's temperature is called ______ energy
thermal