Momentum and Circular Motion

Question 1

Is momentum a scalar or vector quantity?

Answer 1

Vector

Question 2

What are the units for momentum?

Answer 2

Kgms^-1 or Ns

Question 3

How can you investigate the rate of change of momentum?

Answer 3

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

Question 4

What is momentum?

Answer 4

Mass x velocity

Question 5

What is the conservation of momentum dependent on?

Answer 5

That no external forces act

Question 6

What is the equation for impulse?

Answer 6

F x t

Mv - mu

Question 7

How is momentum conserved in an explosion?

Answer 7

The initial momentum is 0. The final momentum is 0. Objects with different masses move in opposite directions with different velocities.

Question 8

How is the conservation of momentum responsible for Newton’s third law?

Answer 8

A force changing the momentum in one direction must be countered by an equal and opposite force to ensure that momentum is conserved

Question 9

What type of collision is kinetic energy conserved?

Answer 9

Elastic

Question 10

What is an example of an elastic collision?

Answer 10

Alpha particles being scattered by a nucleus

Question 11

On a velocity-time graph, how could you see a change in direction?

Answer 11

Negative velocity

Question 12

If you want an object to stop moving, what must be removed?

Answer 12

The objects momentum

Question 13

How can you solve the conservation of momentum in two dimensions?

Answer 13

Resolve each of the momentum vectors after the collision in to their vertical and horizontal components

Question 14

How do you convert from degrees to radians?

Answer 14

pi/180

Question 15

What is angular displacement?

Answer 15

The vector measurement of the angle through which something has turned

Question 16

What is angular velocity?

Answer 16

The rate at which the angular displacement changes

Question 17

Why does a body moving at a constant speed in a circular path need a resultant force acting on it?

Answer 17

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

Question 18

What factors affect the centripetal force?

Answer 18

Mass, velocity and radius

Question 19

If there was no resultant force acting on a body, what direction would the body travel?

Answer 19

In a straight line along the tangent at the point it was released

Question 20

What are the units for angular velocity?

Answer 20

rads^-1

Question 21

What 2 laws causes a rocket to work?

Answer 21

Newton’s third law

Conservation of momentum

Question 22

State Newton’s second law in terms of momentum

Answer 22

The force acting on a body is equal to the rate of change of momentum

Question 23

Describe how you could check experimentally that momentum is conserved between 2 objects

Answer 23

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

Question 24

How does Newton’s cradle work?

Answer 24

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