P2.3 Forces In Action

Question 1

How do you change the shape of an object

Answer 1

Compression

Tension/stretching

Bending

Question 2

What is a plastic material

Answer 2

A material that becomes deformed when you apply a force and does not return to its original shape when you remove the force

Question 3

What is an elastic material

Answer 3

An object that returns to its original shape when you remove a force

Question 4

What type of relationship does force and extension have

Answer 4

A linear relationship

They are directly proportional

Question 5

What is a linear relationship

Answer 5

One where a straight line passes through (0,0)

Question 6

What is the Limit of proportionality

Answer 6

The point where extension is no longer proportional to force

Question 7

What is the elastic limits

Answer 7

The point beyond which an object does not return to its original shape when the force is removed

Question 8

What is Hookes Law

Answer 8

The extension of a spring is proportional to the force until you reach the limit of proportionality

Question 9

What is the equation for the force exerted by a spring

Answer 9

Force exerted by a spring (N) = spring constant (N/m) ✖️ extension (m)

Question 10

What is the spring constant

Answer 10

It tells you how stiff an object is

Question 11

How do you calculate the energy transferred in stretching a spring

Answer 11

Energy transferred (J) = 0.5 ✖️spring constant (N/m) ✖️ (extension)2

Question 12

What type of relationship exists between force and extension when you stretch an elastic band?

Answer 12

Non linear

Question 13

What happens to the stiffness when you blow a balloon

Answer 13

First the rubber is stiff
Once you start blowing it up it requires less force to produce extension

It then becomes stiffer again

Question 14

What is a gravitational field?

Answer 14

A region where a mass experiences an attractive force

Question 15

What is the equation for gravity force

Answer 15

Gravity force (N) =. Mass (kg) ✖️gravitational field strength (N/kg)

Question 16

What is gravitational field strength

Answer 16

The measure of the force on a 1Kg mass when it is in a gravitational field

Question 17

Does mass change

Answer 17

No

Question 18

What is weight

Answer 18

The force of the earth on an object

Question 19

How do you calculate weight

Answer 19

Weight (N) = mass (kg) ✖️gravitational field strength

Question 20

What is gravitational potential energy

Answer 20

The energy transferred to a gravity store when you lift an object in a gravitational field

Question 21

How do you calculate gravitational potential energy

Answer 21

Gpe (J) = mass x gravity x height

Question 22

What is a pivot?

Answer 22

The point about which forces act to produce turning effects

Question 23

What is a moment

Answer 23

The turning effect of a force

Question 24

How do you calculate the moment of a force

Answer 24

Moment of a force (Nm) = force x distance

Question 25

What is the principle of moments?

Answer 25

An object is balanced if the anti-clockwise moments are equal to the clockwise moments about the pivot F1D1 = F2D2

Question 26

What is a force multiplier

Answer 26

A factor that greatly increases the effectiveness of a force

Question 27

What is a lever and what does it do?

Answer 27

An object that won’t bend with a pivot A force applied at one end produces a force in the opposite direction at the other end It transmits forces by rotating about a pivot

Question 28

What is the effort

Answer 28

The force you apply (to the lever )

Question 29

What is the load?

Answer 29

The force that you are trying to move The force that the lever exerts of the load

Question 30

How do you calculate the mechanical advantage?

Answer 30

Load ➗ effort

Question 31

How do gears transmit forces?

Answer 31

If you make a small cog rotate with a large force it will make a larger cog rotate. The bigger cog will exert a bigger force, but will not move as far You can use gears to change the direction in which the rotating force acts or the speed at which it rotates.

Question 32

How does pressure in a fluid cause a force

Answer 32

The pressure in a fluid produces a force at right angles to any surface

Question 33

How do you calculate pressure

Answer 33

Force (N) ➗ area (m2)

Question 34

What is a hydraulic machine

Answer 34

A machine that uses a liquid to transmit a force Made of two pistons connected by a pipe. When you push on one piston the pressure is transmitted through the liquid and the other piston moves