Dynamics

Question 1

Newton’s First Law

Answer 1

Any mass has a tendency to maintain its current state of motion

Inertia is the property of mass, by which it will resist to an attempt to change its state of motion

An object at rest will remain at rest unless acted upon by a force

An object in motion will remain in motion unless acted upon by a force

Question 2

Newton’s second law of motion

Answer 2

F_net = ma

Question 3

Newton’s Third Law

Answer 3

Action - Reaction

every action has an opposite and equal reaction

Question 4

Air resistance (drag)

Answer 4

F_R

Question 5

Net force

Answer 5

F_net = sum of all forces acting on an object

F_net = m • a

Question 6

F_G / mg expression

Answer 6

F_G = m • g

Question 7

Newton

Answer 7

1kg m/s²

(A force that would give a 1kg mass an acceleration of 1m/s²)

Question 8

One Newton

Answer 8

is the force applied to an object with a mass of 1kg, that will accelerate it at 1m/s²

Question 9

One Kilogram

Answer 9

is the mass of an object that will accelerate at 1 m/s² when it experiences a force of 1N

Question 10

1 m/s²

Answer 10

is the acceleration of an object with a mass of 1kg when it experiences a force of 1N

Question 11

What is a force

Answer 11

A force is a push or pull. Forces are responsible for changes in motion

Question 12

(N2)

When the net force is zero …

Answer 12

• an object is at rest

or

• an object is in uniform motion (constant velocity)

In both cases, acceleration is ZERO

Question 13

Force of Static Friction

Answer 13

µ_s is the coefficient of static friction

Fs = µ_S • F_N

F_N = mg cos ø

Question 14

Force of Kinetic Friction

Answer 14

µ_k is the coefficient of kinetic friction

FK = µ_K • F_N

F_N = mg cos ø

Question 15

F_G

Answer 15

Gravitational Force (weight)

F_G = mg

• points towards the centre of the Earth
• directly proportional to the mass of the object

Question 16

F_A

Answer 16

Applied Force

a generic term for any push or pull

Question 17

F_N

Answer 17

contact force (between objects)

is perpendicular to the separation surface between objects

Question 18

F_R

Answer 18

Air Resistance (drag)

• points opposite the direction of velocity
• directly proportional to the speed of the object squared

Question 19

F_T

Answer 19

Tension Force

• occurs in a string or rope
• has direction only at the two ends

Question 20

F_S

Answer 20

Static Friction

F_S = µ_{<span>s</span>}F_N

• µ_s is the coefficient of static friction
• acts before objects start moving in relation to each other

Question 21

F_K

Answer 21

Kinetic Friction

F_K = µ_kF_N

• µ_k is the coefficient of kinetic friction
• acts after objects start moving in relation to each other

Question 22

Newtons Fourth Law

Fg = ?

G = ?

Answer 22

two masses are equally attracted with equal and opposite forces.

Fg = G • m₁m₂ / r²

Fg = G • mM_E / R_E²

Fg/m = g = G • M_E / R_E²

g = G • M_E / R_E²

G = 6.673 x 10^-11 N•m² / kg²