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21 Cards in this Set
- Front
- Back
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What is Newton's Third Law of Motion?
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Newton's Third Law of Motion:
Forces come in pairs. Whenever one object exerts a force on a second object, the second object exerts a force on the first object that is equal in MAGNITUDE but opposite in DIRECTION. |
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What else is Newton's Third Law called?
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Newton's Third Law of Motion is also referred to in this way:
"For every action, there is an equal and opposite reaction." |
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Explain how objects can move if all forces are equal and opposite, according to Newton's 3rd Law?
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The forces act on different objects: Action force acts on object 1; Reaction force acts on object 2.
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What happens if two object have the same mass?
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If two object have the same mass:
They will experience equal accelerations in opposite directions. |
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In a head-on collision between a large dump truck and a small pickup truck, which truck will experience the greatest force?
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They will experience equal but opposite forces.
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In a head-on collision between a large dump truck and a small pickup truck, which truck will experience the greatest change in velocity?
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The less massive truck will have the greater change in velocity.
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In a head-on collision between a large dump truck and a small pickup truck, which truck will experience the greatest acceleration?
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The less massive truck will have the greatest acceleration.
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In a head-on collision between a large dump truck and a small pickup truck, which truck would you rather be in during the collision -- the more massive or less massive truck?
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It would be safer to be in the dump truck because it would have a much smaller acceleration.
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Explain how rockets are an example of Newton's 3rd Law.
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For every action, there is an equal and opposite reaction: The hot gas exerts a forward force on the rocket, propelling it forward; the rocket exerts an opposite force on the gas molecules pushing them out the back of the rocket.
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How can Newton's 3rd Law explain the conservation of momentum?
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Within a system, momentum can never be lost or gained -- it is always conserved.
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What is momentum?
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momentum: the quantity of motion that an object has because of its mass and velocity.
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How is momentum calculated?
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momentum = mass x velocity
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What is the letter for momentum in calculations?
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The letter for momentum in calculations:
p |
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What is the calculation for momentum?
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Momentum calculation:
p = m x v |
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What are the units for momentum?
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Units for momentum:
kilogram-meters per second, or kg m/s |
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Is momentum a vector or scalar quantity?
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Momentum is a Vector quantity, because it has a direction
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What is the law of conservation of momentum?
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The law of conservation of momentum: The total momentum of a group of objects does not change unless outside forces (usually friction) act upon the objects.
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How could a slow-moving elephant and a bullet fired out of a gun have similar momentums?
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The elephant has a small velocity, but its mass is very large.
The bullet has a small mass but it has a very large velocity. |
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Solve this problem:
A 3,000-kg car traveling at 20 m/s crashes head-on into a 2,500-kg car traveling at 40 m/s. After the collision, the 3,000-kg car has a velocity of 15 m/s. What is the velocity of the 2,500-kg car, assuming there is no friction? |
Answer not in notes.
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What is the momentum of a 100-gram baseball that is traveling at 225 m/s?
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p = m x v
m = 100 g = .1 kg v = 225 m/s p = 22.5 kg m/s |
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What is the velocity of an 85-kg jogger traveling with a momentum of 500 kg m/s?
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v = p / m
m = 85 kg p = 500 kg m/s v = 5.88 m/s |
