forces and motion

Question 1

average speed formula

Answer 1

average speed=distance/time

Question 2

acceleration

Answer 2

the rate of change in velocity

Question 3

acceleration formulas

Answer 3

a= v-u/t
a=v2-u2/2s (distance) (suvat)

Question 4

important note about acceleration

Answer 4

change in direction is still acceleration

Question 5

vector quantities

Answer 5

• velocity
• displacement
• force
• acceleration
• momentum

Question 6

scalar quantities

Answer 6

• speed
• distance
• mass
• energy
• density

Question 7

difference between scalar and vector

Answer 7

scalar= magnitude (size)
vector= magnitude AND DIRECTION

Question 8

velocity formula

Answer 8

v=s/t

Question 9

how forces can affect bodies

Answer 9

• change their shape
• change their speed
• change their direction

Question 10

weight

Answer 10

the name given to the force of gravity on a mass

Question 11

electrostatic force

Answer 11

the force between two charges

Question 12

thrust

Answer 12

the force pushing an object forward

Question 13

air resistance

Answer 13

the friction of the air on a moving object

Question 14

upthrust

Answer 14

the force of a fluid pushing on an object

Question 15

compression

Answer 15

forces that are squashing an object

Question 16

tension

Answer 16

forces that are stretching an object

Question 17

normal reaction force

Answer 17

a force due to contact between two objects

Question 18

force formula

Answer 18

force=mass x acceleration
f=ma

Question 19

relationship between force and acceleration

Answer 19

directly proportional

gradient of force, acceleration graph: f/a=m

Question 20

relationship between acceleration and mass

Answer 20

inversely proportional

Question 21

stopping distance

Answer 21

stopping distance=thinking distance + braking distance

Question 22

factors affecting thinking distance

Answer 22

• intoxication
• distractions (e.g mobile phones)
• tiredness

Question 23

factors affecting braking distance

Answer 23

• condition of tyres and brakes
• condition of road and weather
• mass of vehicle (heavier=takes longer to stop)

Question 24

thinking distance

Answer 24

distance a vehicle travels in the time it takes for a driver to react to a situation and apply the brakes

Question 25

braking distance

Answer 25

the distance a vehicle takes to stop once the driver has applied the brakes

Question 26

terminal velocity

Answer 26

the maximum velocity an object can reach as it falls through a fluid

Question 27

weight formula

Answer 27

weight= m x g

Question 28

why g is smaller on the moon than on earth

Answer 28

the moon has a lower density and lower mass

Question 29

hooke's law

Answer 29

the extension of a spring is directly proportional to the force applied

Question 30

hooke's law force formula

Answer 30

force=extension x spring constant

Question 31

elastic limit

Answer 31

- material no longer shows elastic behavior - material is permanently deformed

Question 32

elastic bands

Answer 32

elastic bands do not obey hooke's law because the extension is NOT directly proportional to the force applied

Question 33

momentum formula

Answer 33

momentum=mass x velocity P=m x v

Question 34

momentum conservation

Answer 34

the momentum before is equal to the momentum after in any collision or explosion provided no external forces act on the system

Question 35

elastic collisions

Answer 35

when objects don't stick together after the collision

Question 36

elastic collision equation

Answer 36

m1u1+- m2u2= +-m1v1+-m2v2

Question 37

plastic collision

Answer 37

when the objects stick together after the collision

Question 38

plastic collision equation

Answer 38

m1u1+-m2u2= v(m1+m2)

Question 39

isolated system

Answer 39

no external forces acting on the system

Question 40

force

Answer 40

the rate of change in momentum

Question 41

force and momentum formula

Answer 41

F=ΔP/t

Question 42

principle of moments

Answer 42

for a system to be balanced the sum of clockwise moments must be equal to the sum of anti-clockwise moments

Question 43

moment formula

Answer 43

moment= force x perpendicular distance from pivot

Question 44

car safety

Answer 44

- crumple zones - air bags - side bars - collapsable steering wheels - designed to increase the time taken for a driver or passanger to change momentum because F=

Question 45

newtons 3 laws

Answer 45

1. an object will not change its motion unless a force acts on it 2. f=mass x acceleration 3. whenever two objects interact, they exert equal and opposite forces on each other