P5 - Forces

Question 1

Vector quantities

Answer 1

They have a magnitude and a direction
force
velocity
displacement
acceleration
momentum

Question 2

Scalar quantities

Answer 2

They only have a magnitude and no direction
speed
distance
mass
temperature
time

Question 3

Force

Answer 3

A force is a push or a pull on an object that is caused by it interacting with something. They are either contact or non-contact forces

Question 4

Contact forces

Answer 4

When two objects have to be touching 
friction
air resistance
tension in ropes
normal contact force

Question 5

Non-contact

Answer 5

When two objects don’t need to be touching
Magnetic force
gravitational force
electrostatic force

Question 6

Why weight and mass are not the same

Answer 6

Mass is the amount of ‘stuff’ in an object.
Weight is the force acting on an object due to gravity.
Gravitational field strength varies with location.

Question 7

Gravitational field strength on the moon and earth

Answer 7

Moon - 1.6 N/Kg

Earth - 9.8 N/Kg

Question 8

Weight equation

Answer 8

Weight = Mass x Gravitational field strength

Question 9

Work done equation

Answer 9

Work done = Force x Distance

Question 10

Applying a force to an object

Answer 10

it can cause the object to stretch, compress or bend.An object has been elastically deformed if it can go back to its original shape and length after the force has been removed. An object is inelastically deformed if it doesn’t return to it’s original shape and length after the force has been removed.

Question 11

Force equation

Answer 11

Force is directly proportional to the extension

F = ke

Question 12

Elastic potential energy equation

Answer 12

E = 1/2ke^2

Question 13

Difference between Distance and Displacement

Answer 13

Distance is how far the object has moved. It is a scalar quantity so it doesn’t involve direction.
Displacement is a vector quantity. It measures the distance and direction in a straight line from an object’s starting point to its finishing point.

Question 14

Distance traveled equation

Answer 14

Distance traveled = speed x time

Question 15

Acceleration

Answer 15

The change in velocity in a certain amount of time

A = Change in Velocity / Time

Question 16

Uniform/constant acceleration

Answer 16

v^2 - u^2 = 2as

Question 17

Newton’s first law

Answer 17

If the resultant force on a stationary object is zero, the object will remain stationary. If the resultant force on a moving object is zero, it’ll just carry on moving at the same velocity.

Question 18

Newton’s second law

Answer 18

The larger the resultant force acting on the object, the more the object accelerates.
Resultant force = mass x acceleration

Question 19

Newton’s third law

Answer 19

When two objects interact, the forces they exert on each other are equal and opposite

Question 20

Stopping distance equation

Answer 20

Stopping distance = Thinking distance + Breaking distance

Question 21

Thinking distance is affected by:

Answer 21

• your speed

- your reaction time

Question 22

Breaking distance is affected by:

Answer 22

• Your speed
• The weather
• The condition of your tyres
• How good your breaks are

Question 23

Momentum equation

Answer 23

Momentum = mass x velocity