forces, movement & changing shape

Question 1

what is a force

Answer 1

push or pull that arises from the interaction between objects

Question 2

what are the 2 different types of forces

Answer 2

gravitational force

reaction force

Question 3

what is a reaction force

Answer 3

When an object rests on a surface, the surface exerts a push force on the object

This reaction force acts at right angles (perpendicular) to the surface

Question 4

what is gravitational force

Answer 4

There is a gravitational force of attraction between all objects with mass

The more massive the object, the greater the gravitational force exerted by it

Question 5

thrust

Answer 5

a force produced by an engine that speeds up the motion of an object

Question 6

upthrust

Answer 6

When an object is fully or partially submerged in a fluid, the fluid exerts an upward-acting push force on the object

Question 7

air resistance

Answer 7

Air resistance occurs when particles of air collide with an object moving through it and slows its motion

Question 8

drag force

Answer 8

a type of frictional force that occurs when an object moves through a fluid (a gas or a liquid)

The particles in the fluid collide with the object moving through it and slow its motion

Question 9

friction

Answer 9

frictional forces always oppose the motion of an object, causing it to slow down

Friction occurs when two surfaces move over one another

Question 10

magnetic force

Answer 10

There is a magnetic force between objects with magnetic poles

Like poles repel one another, opposite poles attract one another

Question 11

tension

Answer 11

Tension occurs in an object (like a rope or spring) that is stretched

When a pull force is exerted on each end of an object, tension acts across the length of the object

Question 12

When a force acts on an object, there are 3 effects

Answer 12

change speed

change direction

change shape

Question 13

scalar

Answer 13

have magnitude

Question 14

vectors

Answer 14

have magnitudes and not direction

Question 15

example of scalar

Answer 15

mass

Question 16

example of vector

Answer 16

weight, forces

Question 17

what is a resultant force

Answer 17

a single force that describes all of the forces operating on a body

Question 18

resultant force determines

Answer 18

The direction in which the object will move as a result of all of the forces

The magnitude of the net force experienced by the object

Question 19

friction

Answer 19

A force which opposes the motion of an object

Question 20

when forces are balanced, the resultant force will be

Answer 20

zero

Question 21

stopping distance is

Answer 21

the total distance travelled during the time it takes to stop in an emergency

Question 22

to calculate stopping distance,

Answer 22

Thinking distance + Braking distance

Question 23

thinking distance

Answer 23

the distance travelled in the time it takes the driver to react to an emergency and prepare to stop

Question 24

factors affecting thinking distance

Answer 24

speed of car
reaction time of driver

Question 25

reaction time

Answer 25

A measure of how much time passes between seeing something and reacting to it

Question 25

factors affecting reaction distance

Answer 25

Tiredness Distractions (e.g. using a mobile phone) Intoxication (i.e. consumption of alcohol or drugs)

Question 26

breaking distance

Answer 26

the distance travelled under the braking force in metres (m)

Question 27

factors affecting stopping distance

Answer 27

speed mass road condition reaction time

Question 28

terminal velocity

Answer 28

he fastest speed that an object can reach when falling

Question 29

when is terminal velocity reached

Answer 29

when the upward and downward acting forces are balanced / when the resultant force acting on the object reaches 0

Question 30

falling objects experience two forces:

Answer 30

weight air resistance

Question 31

as object falling speed increases, what happens to air resistance

Answer 31

increases

Question 32

why does air resistance increase as speed does in a falling object

Answer 32

because the object collides with air particles as it moves through the air The faster the object is travelling, the more collisions it has with the air particles