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Kinetic Energy
Potential Energy
Momentum & Collisions
More Collisions
Vocab / Formulas
100
Where would a ball rolling down a hill have maximum kinetic energy?
At the bottom of the hill, where its speed is a maximum
100
Which part of the gravitational potential energy formula can we change to increase an object's PE?
Its height
100
What letter or symbol do we use to represent momentum in physics?
A lowercase "p"
100
What are the two kinds of collisions we've been studying lately?
Elastic and inelastic collisions
100
What is the formula used to calculate gravitational potential energy?
PE = mass x gravity x height
200
What is the kinetic energy of a 2 kg object moving at 3 m/s?
9 J
200
What unit do we use to measure energy?
The Joule
200
Momentum is equal to...?
mass x velocity
200
What is the formula we use for an elastic collision?
m1v1 = m2v2
200
What kind of collisions do we use this formula for? m1v1 = (m1 + m2)v2
Inelastic collisions
300
What is the mass of an object with a kinetic energy of 50 J and a velocity of 5 m/s?
4 kg
300
How much potential energy does a 9 kg object sitting on the edge of a 200 m high cliff have?
17640 J or 18000 J
300
In a collision, an object strikes another at a given speed. After the impact, the first object stops completely and the second object moves with the same exact speed that the first was originally going. What kind of collision is this?
Elastic - the objects bounced off of each other and kinetic energy was conserved
300
A 19 kg object collides with a second stationary object at 4 m/s. After the impact, the new speed of the first object is 0 m/s, and the new speed of the second object is 8 m/s. What is the second object's mass?
9.5 kg
300
What is the formula used to calculate the kinetic energy of an object?
KE = (1/2)mv^2
400
How much kinetic energy does a 12345 kg object traveling at 678 m/s have?
2.84 x 10^9 J or 2837399490 J
400
How high off the ground is a 28 kg object with 650 J of gravitational potential energy?
2.37 J or 2.32 J
400
DAILY DOUBLE - THIS QUESTION IS WORTH 800 POINTS... After an inelastic collision, two objects move at half the speed that the first object was originally traveling at. What is the second object's mass compared to the first's?
The second object's mass is the same as the first
400
A 2 kg object collides and sticks to another object of the same mass. Before the collision, the first object travels at 21 m/s. How fast do the objects travel after the impact?
10.5 m/s
400
What is the difference between an elastic and inelastic collision?
In an elastic collision, the kinetic energy of an object is conserved after the impact, whereas some of the kinetic energy is transformed in an inelastic collision or The objects bounce off of each other in an elastic collision and stick together in an inelastic collision
500
How fast does a 33 kg object with 555 J of kinetic energy travel?
About 5.8 m/s
500
A 39 kg object has about 443 J of gravitational potential energy and is 7 m off the ground. What is the acceleration due to gravity where the object is at?
1.62 m/s^2 (the object is on the moon)
500
What does the Law of Conservation of Momentum state?
That the total momentum before a collision must equal the total momentum after the collision
500
DAILY DOUBLE - THIS QUESTION IS WORTH 1000 POINTS... A 1000 kg car driving behind a motorcycle rear-ends it. Before the collision, the car was moving at 10 m/s, while the motorcycle was moving at 3 m/s. After the collision, the car's new speed is 6 m/s, and the motorcycle's is 12 m/s. What is the motorcycle's mass?
444 kg
500
When both objects involved in a collision are initially in motion, what formula should we use?
m1v1b + m2v2b = m1v1a + m2v2a