7 Laws of Motion and Momentum

Question 1

State Newton’s First Law

Answer 1

An object will remain at rest or with constant velocity in a straight line unless acted upon by a resultant force.

Question 2

State Newton’s Second Law

Answer 2

Force is directly proportional to the rate of change of momentum IN THE SAME DIRECTION
F=ma

Question 3

State Newton’s Third Law

Answer 3

If object A exerts a force on object B, object B also exerts an equal and opposite force on object A

Question 4

State the four fundamental forces

Answer 4

Gravitational
Electromagnetic
Strong Nuclear
Weak Nuclear

Question 5

Equation for momentum

Answer 5

momentum = mass x velocitu

Question 6

State the principle of conservation of momentum

Answer 6

For a system of interacting objects, the total momentum in a specified direction remains constant, as long as no external forces act upon this system.

Total momentum before = total momentum after

Question 7

Define elastic and inelastic collisions

Answer 7

Elastic collisions - momentum, kinetic energy and total energy are conserved.
Inelastic collisions - momentum and total energy are conserved but NOT kinetic energy.

Question 8

Derive F=ma

Answer 8

Newton’s 2nd Law: F=Δp/Δt
F=mv-mu/t
F=m(v-u/t)
F=ma

Question 9

Define impulse

Answer 9

Change of momentum.
F=Δp/Δt
F x Δt = Δp
impulse = change of momentum

Question 10

What does the area under a force-time graph represent?

Answer 10

Area = Δp
area = impulse

Question 11

Resolving momentum in the x direction?

Answer 11

total initial momentum = total final momentum
m1 v0 = m1 v1 cosθ1 + m2 v2 cosθ2

Question 12

Resolving momentum in the y direction?

Answer 12

total initial momentum = total final momentum
0 = m1 v1 sinθ1 + m2 v2 sinθ2