Forces

Question 1

What is a force?

Answer 1

A push or pull that acts on an objects. Force is measured in Newtons.

Question 2

What is a contact force?

Answer 2

Force that physcially touches the object.

Question 3

What is a non contact force?

Answer 3

Force that are not physically touching an object.

Question 4

Examples of contact forces.

Answer 4

• Air resistance
  -Tension
  -Friction
  -Thrust
  -Upthrust
  -Normal force reaction

Question 5

Examples of non contact forces

Answer 5

-Gravity
-Magnetic force
-Electrostatic force

Question 6

How can you show forces acting upon an object.

Answer 6

Using a free body diagram, each force represented by arrow and length of arrow shows magnitude.

Question 7

What is a resultant force?

Answer 7

Overall forces that act upon an object.

Question 8

When is an object in equillibrium and how to show on free body diagram?

Answer 8

When all forces add up to give a resultant force of 0.

Question 9

How to add forces?

Answer 9

-Forces in same direction - add
Forces in different direction - subtract
Equal forces = 0

Question 10

Difference between velocity and speed?

Answer 10

Speed is a measure of how fast, velocity is speed and distance combined

Question 11

Difference between scalar and vector?

Answer 11

Slaar has a magnitude quantity only. Vector includes magnitude and direction.

Question 12

Give examples of scalar measures.

Answer 12

Temperature
Mass
Energy
Distance
Speed
Density

Question 13

Give examples of vector quantities.

Answer 13

Force
Weight
Displacement
Velocity
Acceleration
Momentum

Question 14

What is the equation for gradient?

Answer 14

Change in x/ divided by change in y

Question 15

What is work done?

Answer 15

Energy transferred when a force moves an object through a distance.

Question 16

Calculation for work done?

Answer 16

Energy = force in newtons x distance.in metres

Question 17

When is an object elastically deformed?

Answer 17

When it is strecthed and returns to its original shape and length after force is removed.

Question 18

When is an object inelastically deformed?

Answer 18

When it is stretched but doesn’t return to original shape and length once force is removed.

Question 19

How to calculate force applied on a spring with extension?

Answer 19

force in newtons = spring constant in newton/metres x extension in metres.

Question 20

What does spring constant rely on?

Answer 20

Material you are stretchin - stiffer spring has greater spring constant.

Question 21

What is the limit of proportionality?

Answer 21

Limit to the amount of force you can apply on an object for extension to increase proportionally.

Question 22

What is the equation for a person travelling at constant speed?

Answer 22

distance travelled in metres = speed in m/s x time in seconds

Question 23

What is acceleration?

Answer 23

How quickly velocity is changing.

Question 24

Formula for average acceleration over a certain time period?

Answer 24

Question 25

What is the equation for uniform acceleration?

Answer 25

Sometimes known as constant acceleration

Question 26

What do distance time graphs show?

Answer 26

How far an object is travelling from a cetrain point in certain time. Gradient of the line = speed, so steeper line = faster speed. Curved line upward when accelerating and curved line downwards when decelerating - use tangent to determine speed at point.

Question 27

What do velocity time graphs show?

Answer 27

Show an objects motion. Time = horizontal and Velocity = vertical gradient of line shows acceleration area beneath line shows distance travelled.

Question 28

How to calculate resultant force?

Answer 28

resultant force (N) = acceleration in metres/seconds squared x mass (kg)

Question 29

How to increase top speed of vehicle?

Answer 29

- reduce drag (streamlined/less grip tyres) - increase vehicle engine power

Question 30

What is terminal velocity?

Answer 30

When an object reaches a constant speed of falling because gravity and air resistance are equal and it stop accelerating.

Question 31

What is Newton's first law?

Answer 31

If the resultant force on a stationary object is zero, the object will remain stationary. If resultant force on a moving object is zero, its velocity will remain the same as it moves. If there is a non zero resultant force on an object, it's velocity will change (it will accelerate in the direction of the force)

Question 32

What is Newton's second law?

Answer 32

Question 33

What is Newton's third law?

Answer 33

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

Question 34

How to calculate stopping distance?

Answer 34

Stopping distance = thinking distance + braking distance

Question 35

What is thinking distance?

Answer 35

Distance vehicle travels during time between driver seeing vehicle and applying brakes (reaction time)

Question 36

What is thinking distance affected by?

Answer 36

- Speed of vehicle - Reaction time - affected by drugs/alcohol, distractions + tiredness

Question 37

What is braking distance?

Answer 37

Distance vehicle travels after breaks are applied and comes to a complete stop.

Question 38

What is braking distance affected by?

Answer 38

- Speed of vehicle - Quality of breaks - Tyre quality - Weather conditions

Question 39

How to calculate momentum?

Answer 39

Question 40

What is the conservation of momentum?

Answer 40

Total momentum before collision is equal to total momentum after