Unit 2 - Forces and Newton's Laws Flashcards Preview

GAMSAT (SIII) - Physics > Unit 2 - Forces and Newton's Laws > Flashcards

Flashcards in Unit 2 - Forces and Newton's Laws Deck (27)
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1
Q

What is an external force

A

Force originating from outside of an object

2
Q

What is Newton’s first law

A

An object remains at rest or if in motion at a constant velocity unless acted on by a net external force

3
Q

Summarise Newton’s first law

A

No resultant force = no acceleration

4
Q

What is Newton’s second law

A

Acceleration is proportional to the net force and inversely proportional to the mass

5
Q

Equation from Newton’s second law

A

F = ma

6
Q

What is Newton’s second law

A

If 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`

7
Q

What is weight

What is the equation for determining weight

A

The force of gravity

W = mg

8
Q

What is g

What can we approximate it to

A

9.81

10

9
Q

What is mass

A

The measure of inertia of an object

10
Q

_______ is constant but __________ changes due to differences in gravity

A

Mass

Weight

11
Q

What is a normal force

A

Force exerted by surfaces to prevent solid objects pushing through one another

12
Q

Forces PERPENDICULAR are

A

Normal

13
Q

Forces PARALLEL are

A

Frictional

14
Q

Give an instance where the normal force may not equal mg

A

When contact forces are not horizontal or there are extra vertical forces present

15
Q

When are frictional forces present

A

When two surfaces are sliding over one another

16
Q

Frictional forces are characterised by

A

The frictional coefficient

U

17
Q

What is the equation connecting frictional force and the normal force

Define the terms of this equation

A

Ff = u . Fn

Ff = frictional force 
u = frictional coefficient 
Fn = normal force
18
Q

What is static frictional force

A

Between a static object and the surface that it is resting on

19
Q

What equation must be used to determine the MAX force required to move an object

Define the terms of this equation

A

Fmax = u . Fn

Fmax -force required to move
u - frictional coefficient
Fn - normal force

20
Q

If you apply a force above Fmax what is seen

A

Kinetic frictional force will be exerted on it

21
Q

What is the equation for determining the kinetic frictional force

A

Fk = u . Fn

Where Fk = kinetic frictional force
u = friction coefficient
Fn = normal force

22
Q

Is there any static frictional force for a moving object

A

NO

Instead we would have kinetic frictional force

23
Q

For an object on an incline plane which is not moving what term would give the normal force

A

Mg cos theta = N

24
Q

Define tension

A

The force exerted by a rope/cable is the force of tension T

25
Q

Tension is only able to

A

Pull

26
Q

Steps for calculating tension in a system

A

1) draw forces acting on the object
2) write down F=ma for direction of tension
3) solve

27
Q

Cos 60 =

A

0.5