P3.2 Using Physics To Make Things Work

Question 0

How can you find the centre of mass of a flat object?

Answer 0

Weight of a string
Make holes
Put string in
Drawn straight down
Where lines cross
If freely suspended an object will come to rest with it centre of mass directly below the point of suspension

Question 1

What’s the centre of mass?

Answer 1

The centre of mass of an object is that point at which the mass of the object may be thought to be concentrated

Question 2

For a symmetrical object where is the centre of mass?

Answer 2

Along the axis of symmetry

Question 3

How do you find the time for a pendulum?

Answer 3

T=1/frequency

Question 4

If the length of a string is doubles the frequency is _____ than half

Answer 4

More

Question 5

What affects the time period of a pendulum?

Answer 5

Length of string

Question 6

What’s a moment?

Answer 6

The turning effect of a force

Question 7

How do you find the moment?

Answer 7

M=f x d

Question 8

What is special about the distance?

Answer 8

It’s perpendicular from the pivot

Question 9

If an object isn’t turning what can you tell?

Answer 9

The total clockwise moment = total anticlockwise moment

Question 10

What’s total moment?

Answer 10

Adding the moment of all the forces on the object

Question 11

What does a lever do?

Answer 11

Force multiplier

Load is larger than the effort

Question 12

How is an object stable?

Answer 12

If it stays or returns equilibria when moved

Question 13

How is an object supported?

Answer 13

Large base

Low COM

Question 14

When is an object unstable?

Answer 14

When the line of action is outside the base,mother will be a resultant moment that causes it to topple over

Question 15

Why are liquids used in hydraulics?

Answer 15

They are incompressible

Question 16

What’s pressure and how you find it?

Answer 16

The force on a given area

P=f/a

Question 17

Explain a hydraulic system?

Answer 17

Liquids are incompressible
If you push pressure is exerted in all directions
A larger area applies a larger force

Question 18

A larger piston moves ____ distance?

Answer 18

Less

Question 19

Doubling the force will move ____ the distance?

Answer 19

Half

Question 20

What’s circular motion?

Answer 20

Must be pulled to the centre

Speed makes it move to the side

Question 21

How are the forces imbalanced in circular motion?

Answer 21

Direction is changes
So velocity is
So it’s accelerating

Question 22

What’s the centripetal force?

Answer 22

Resultant force

Force pulling it to the centre of the circle

Question 23

What are the factors increase the centripetal force size?

Answer 23

Mass is more
Speed increases
Radius is smaller (shorter string)