Forces

Question 1

non-contact forces (eg.)

Answer 1

Magnetic force
Electrostatic
Gravitational potential

Question 2

contact forces (e.g)

Answer 2

friction, weight, tension, normal contact force, upthrust, thrust

Question 3

types of friction

Answer 3

water and air resitance

Question 4

Formula for weight, mass and gravitational field strengh (include units)

Answer 4

M (Kg) × G (N/kg)

Question 5

gravitational field strenght of earth

Answer 5

9.8 N/kg

Question 6

newton’s third law

Answer 6

1) every action has an equal and opposite reaction

Question 7

Independent variable

Answer 7

decide to change

Question 8

control variable

Answer 8

keep the same to make the experiment fair

Question 9

dependent variable

Answer 9

changes according to changes in independent variable

Question 10

hooke’s law (description)

Answer 10

extension is directly proportional to the force applied

Question 11

hooke’s law (graph)

Answer 11

directly proportional so straight line through origin

Question 12

hooke’s law (equation)

Answer 12

F = ke
(Force = spring constant × extension)

Question 13

Elastic vs plastic deformation

Answer 13

Elastic - bounces back
plastic - doesn’t return to original shape (even if compressed, it will be longer than original)

Question 14

what do arrows in free body diagrams represent?

Answer 14

magnitude and direction - vectors

Question 15

free body diagram definition

Answer 15

free body diagram is a diagram showing the forces acting on an object.

Question 16

In a free body diagram where are the arrows coming from?

Answer 16

The forces are shown as thin arrows pointing away from the centre of the box or dot.

Question 17

how is the ‘body’ or object usually represented?

Answer 17

The object or ‘body’ is usually shown as a box or a dot

Question 18

what is the difference bewteen scalar and vector quantaties?

Answer 18

scalar - magnitude eg mass
vector - magnitude + direction eg forces

Question 19

what is equillibrium?

Answer 19

when two or more forces are in balance so the object keeps moving at a constant speed/ remains stationary

Question 20

acceleration equation and units

Answer 20

a=u-v/t
m/s/s

Question 21

distance-time graphs

Answer 21

—– = stationary
/ = constant speed
( = acceleration
gradient = speed
distance=y, time=x

Question 22

velocity time graphs

Answer 22

_ = stationary
—- = constant speed
/ = constant acceleration
( = not constant accelerating
area under graph = distance travelled
gradient = acceleration
velocity=y, time=x

Question 24

what is a force?

Answer 24

a push or pull on an object caused by it interacting with another object

Question 25

what is a resultant force?

Answer 25

a single force that has the same effect of all the original different forces together

Question 26

how do you work out a resultant force from a diagram?

Answer 26

TIP TO TAIL METHOD 1) move force 1 from the tip of force 2 to the tail of force 2 so that it makes 3 sides of a trapezium 2) the resultant force is the force between the tip of force 2 and the tail of new force 1

Question 27

what is inertia?

Answer 27

the tendency of objects to continue in their state of rest or constant motion

Question 28

newton's second law

Answer 28

2) force = mass × acceleration 1m/s/s = 1N/kg

Question 29

newton's first law

Answer 29

3) inertia (balanced force on still object = stay still - moving object = constant velocity)

Question 30

what does suvat stand for ?

Answer 30

s=displacement u=initial velocity v=final velocity a=acceleration t=time

Question 31

what is termial velocity?

Answer 31

maxium speed achieved by a freely falling object whe forces acting on it are balaced

Question 32

example of terminal velocity - guy jumping out of a plane

Answer 32

1. instant jumping out of a plane only weight is acting downwards 2. as time goes on, weight stays the same but drag increases 3. when drag and weight become balanced the parachutist has reached terminal velocity

Question 33

what is frav?

Answer 33

**f**orces **r**esultant force **a**cceleration (change in) **v**elocity

Question 34

what is inertial mass?

Answer 34

a measure of how difficult it is to change velocity of a object - ratio of force over acceleration

Question 35

what is stopping distance?

Answer 35

thinking distance + braking distance

Question 36

what is thinking distance?

Answer 36

how far the car travels during the driver's reaction time

Question 37

what is braking distance?

Answer 37

how dar the car travels before coming to a stop whilst braking force is applied

Question 38

what affects thinking distance?

Answer 38

reaction time which is affected by - distractions - alcohol and drugs - tiredness

Question 39

average reaction times

Answer 39

0.2s to 0.9s

Question 40

equation for thinking distance

Answer 40

thinking distance = speed x reaction time

Question 41

what affects braking distance?

Answer 41

- friction of road (road conditions eg icy or wet) - mass of car - mass of passengers/ how many passengers - poor condition of tyres and brakes

Question 42

the greater the speed of the vehicle...

Answer 42

the greater the braking force needed to stop the vehicle in a certain distance