Momentum and Circular Motion Flashcards
Is momentum a scalar or vector quantity?
Vector
What are the units for momentum?
Kgms^-1 or Ns
How can you investigate the rate of change of momentum?
Record the movement of an object over time, using light gates and air track. Plot a graph of momentum-time and the gradient will equal the rate of change of momentum
What is momentum?
Mass x velocity
What is the conservation of momentum dependent on?
That no external forces act
What is the equation for impulse?
F x t
Mv - mu
How is momentum conserved in an explosion?
The initial momentum is 0. The final momentum is 0. Objects with different masses move in opposite directions with different velocities.
How is the conservation of momentum responsible for Newton’s third law?
A force changing the momentum in one direction must be countered by an equal and opposite force to ensure that momentum is conserved
What type of collision is kinetic energy conserved?
Elastic
What is an example of an elastic collision?
Alpha particles being scattered by a nucleus
On a velocity-time graph, how could you see a change in direction?
Negative velocity
If you want an object to stop moving, what must be removed?
The objects momentum
How can you solve the conservation of momentum in two dimensions?
Resolve each of the momentum vectors after the collision in to their vertical and horizontal components
How do you convert from degrees to radians?
pi/180
What is angular displacement?
The vector measurement of the angle through which something has turned
What is angular velocity?
The rate at which the angular displacement changes
Why does a body moving at a constant speed in a circular path need a resultant force acting on it?
Velocity is continually changing as the direction of motion is constantly changing, a change in velocity is an acceleration. There must be a force causing this acceleration, the acceleration and force acts towards the centre
What factors affect the centripetal force?
Mass, velocity and radius
If there was no resultant force acting on a body, what direction would the body travel?
In a straight line along the tangent at the point it was released
What are the units for angular velocity?
rads^-1
What 2 laws causes a rocket to work?
Newton’s third law
Conservation of momentum
State Newton’s second law in terms of momentum
The force acting on a body is equal to the rate of change of momentum
Describe how you could check experimentally that momentum is conserved between 2 objects
Using a light gate and air track, make 2 objects collide. Record the velocities before and after the collision. Calculate each objects momentum before and after
How does Newton’s cradle work?
When the first ball hits the second ball, the first ball stops, but its momentum is transferred to the second then the third then the fourth ball. The fifth ball then swings up with nearly the same momentum as the first ball
