9.3- CONSERVATION OF MOMENTUM Flashcards
What is Newton’s third law of motion?
when two objects interact, they exert equal + opposite forces on each other
What must apply for forces to be considered a force pair?
two forces must be of same type, + acting on different objects
What changes when an object is acted on by a resultant force?
its momentum changes
What can there not be if there in no change in momentum of an object?
can be no resultant force on object
How can momentum be transferred?
interactions between objects
Does the total momentum of objects change when they interact?
no
What does the principle of momentum state?
for a system of interacting objects, total momentum remains constant, provided no external resultant force acts on system
What happens to momentum when two object collide with each other and then separate?
momentum of each object changes
What do two objects that collide with each other then separate exert when they are in contact?
exert equal + opposite forces on each other when they’re in contact
When two objects collide with each other then separate, what is the change in momentum of one object equal to?
equal + opposite to change of momentum of other object
When two objects collide with each other then separate, if one object gains momentum, what happens to the other objects and what is total momentum like?
loses equal amount of momentum
total amount of momentum unchanged
What is final momentum equal to?
initial momentum
If colliding objects stick together as a result of collision, what are their final velocities like?
have same final velocity
Testing conservation of momentum?
using motion sensor linked to computer
mass of each trolley measured before test
trolley B at rest, trolley A given push so it moves towards trolley B at constant velocity
computer records + displays velocity of trolley A throughout this time
What does the computer show the velocity of trolley A to be like? (testing conservation of momentum)
velocity of trolley A dropped suddenly when impact took place
What can be used instead of a motion sensor? (testing conservation of momentum)
light gates linked to computer or data logger
How is the experiment done when light gates are used? (testing conservation of momentum)
card attached to trolley A passes through first of two light gates
trolley B positioned so A collides with it just after passing through first light gate
How is the velocity of A before the collision calculated when using light gates? (testing conservation of momentum)
dividing card length by time taken to pass through first gate
How is the velocity of A after the collision calculated when using light gates? (testing conservation of momentum)
dividing card length by time taken to pass through second gate
When two objects moving in opposite directions collide with each other, what does it depend on for the collision to cause the two objects to stop?
mass + initial velocities of the two objects
If two objects moving in opposite directions collide with each other and come to a stop, what does this do to momentum?
momentum of two objects after collision would then be zero
How is the vector nature of momentum taken into account, when two objects are moving in opposite directions?
by assigning numerical values of velocity + or - according to the direction
