7 - Laws of motion and momentum

Question 1

Define momentum

Answer 1

The product of an object’s mass and velocity

Question 2

Is momentum vector or scalar?

Answer 2

Vector so has both magnitude and direction

Question 3

momentum equation

Answer 3

p=mv
momentum = mass x velocity

Question 4

units for momentum

Answer 4

kgms–1 or Ns

Question 5

What is the rate of change of momentum proportional to?

Answer 5

The force acting on the object (Newton’s second law)

Question 6

Change in momentum equation

Answer 6

F= mv-mu / t

Question 7

State the principle of the conservation of momentum

Answer 7

The total linear momentum of a system of interacting bodies is constant

Question 8

Elastic collisions

Answer 8

momentum and total kinetic energy conserved

Question 9

Inelastic collisions

Answer 9

momentum conserved but total kinetic energy is not conserved

Question 10

State Newton’s first law

Answer 10

An object in motion will continue in motion unless there is a resultant force that acts on the object to change its speed, direction or shape

Question 11

State Newton’s second law

Answer 11

The rate of change of momentum is proportional to the force acting on the object F= (m2v-m1u) / t … if mass changes. F=ma is mass stays constant

Question 12

State Newton’s third law

Answer 12

If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. Both forces must be of the same type

Question 13

what is an impulse

Answer 13

change of momentum

or product of the force and the time for which it acts using the newtons second law equation