1) Motion, Forces and Conservation of Energy

Question 1

what is a scalar quantity? examples

Answer 1

size or magnitude but NO direction

-mass, speed, distance , energy

Question 2

what is a vector quantity? examples?

Answer 2

size or magnitude and HAS direction

-force, weight, velocity, displacement, acceleration, momentum

Question 3

what is velocity?

Answer 3

speed in stated direction

Question 4

what is the equation for working out speed?

Answer 4

speed(M/s)= distance m / time s

Question 5

what is the equation for average speed?

Answer 5

av. speed= total distance / total time

Question 6

what does a straight line on a graph tell you about he speed?

Answer 6

constant spped

Question 7

what does a curved line getting stepper tell you about the speed?

Answer 7

accelerating

Question 8

what does a curved line getting flatter tell you about the speed?

Answer 8

decelerating

Question 9

what does a flat line tell you about the speed?

Answer 9

stationary

Question 10

what is the equation for acceleration?

Answer 10

acceleration m/s2 = change in velocity m/s
/ time taken
a=(v-u) / t

Question 11

what is the equation for velocity?

Answer 11

v2 - u2 = 2 x a x X

X is the distance travelled

Question 12

what can you interpret from a velocity/ time graph?

Answer 12

• slope or gradient says acceleration

- area under graph gives distance

Question 13

how do you work out the acceleration on a velocity time graph using the gradient?

Answer 13

acceleration = change in velocity/time taken

Question 14

how can you use laboratory more accurate equipment to measure speed?

Answer 14

-light gates connected to data logger or computer

Question 15

what is the typical speed for walling?

Answer 15

1.5m/s

Question 16

what is the typical speed for running?

Answer 16

3m/s

Question 17

what is the typical speed for cycling?

Answer 17

6m/s

Question 18

what is the typical speed for sound in air?

Answer 18

330m/s

Question 19

what is newtons first law?

Answer 19

• resultant force on stationary object is zero it will stay stationary
• if resultant force on moving object is zero it will stay at same speed and direction

Question 20

what is newtons first law if the resultant force isn’t zero?

Answer 20

-acceleration/ deceleration

Question 21

what is the formula which describes newtons second law?

Answer 21

F= m X a
force(N)= mass (kg) X acceleration (m/s2)

Question 22

what is the definition of weight? and what is it measured in?

Answer 22

• force exerted due to mass and GFS

- measured in newtons

Question 23

what is the equation for weight?

Answer 23

weight= mass X gravity

Question 24

how is weight measured?

Answer 24

-newtonmeter

Question 25

what is the relationship between weight and the gravity?

Answer 25

-weight is directly proportional to value of gravity

Question 26

how would you investigate force and acceleration?

Answer 26

1. set up trolly with light gates and ramp 2. record different velocity and time for different masses on the trolly 3. work out acceleration by dividing velocity by time 4. if changing mass slope must stay the same

Question 27

what conclusion is found after investigating force and acceleration?

Answer 27

-acceleration doesn't depend on mass and stays similar throughout

Question 28

what happens to the speed and velocity of an object moving in a circular motion?

Answer 28

- constant speed | - changing velocity

Question 29

why does circular motion happen? and what force must be acting? example.

Answer 29

- must be a centripetal force - objects move at right angles to it - satellite around earth

Question 30

what is newtons third law?

Answer 30

for every action there is an equal and opposite reaction

Question 31

how does newtons third law act with equilibrium?

Answer 31

-eg if a man is pushing on a wall but the wall won't move because the forces in the system are balanced.

Question 32

how does newtons third aw work with collisions?

Answer 32

- total momentum before equals total momentum after - if 2 cars collide equal and opposite forces - both cars

Question 33

what is the definition of momentum?

Answer 33

product of mass and velocity

Question 34

what is the equation for momentum and what is it measured in?

Answer 34

p= m X v kgm/s2 momentum= mass X velocity

Question 35

what is the definition of force?

Answer 35

rate of change of momentum.

Question 36

what is the equation for force using momentum?

Answer 36

mv - mu F= ---------- t force= change in momentum/ time

Question 37

what is a way of measuring human reaction times? and what is the formula used?

Answer 37

- ruer drop test - hold ruler someone drops catch and measure distance - reaction time= (squ.root) 2 X distance/ gravity

Question 38

what is the average reaction time for a person to respond to a stimulus?

Answer 38

0.2-0.25 seconds

Question 39

what is stopping distance of a vehicle the sum of?

Answer 39

thinking distance + braking distance

Question 40

what are some of the factors which effect stopping distance?

Answer 40

- tired - alcohol+drugs - mass of car - icy or wet conditions

Question 41

what are some of the factors which could effect a drivers reaction time?

Answer 41

- tiredness - age - alcohol - distractions

Question 42

what is a danger of large decelerations?

Answer 42

typic forces of 10,000N exhorted on car

Question 43

what is the formula for change in gravitational potential energy?

Answer 43

GPE= m X g X change in vertical height

Question 44

what is the formula for kenetic energy?

Answer 44

kE= 0.5 X m X v2

Question 45

what is meant by conservation of energy?

Answer 45

- can be stored, transferred or dissipated | - not created or destroyed

Question 46

how is energy changing when a ball is rolled up a slope?

Answer 46

-turns from kinetic energy to gravitational potential energy

Question 47

how is energy change when a bat hits a ball?

Answer 47

- kinetic energy - thermal energy - sound energy

Question 48

how is energy changed when a rock is dropped from a cliff?

Answer 48

- gravitational potential energy | - kinetic energy

Question 49

how is energy changed when a car is slowing dow?

Answer 49

- kinetic energy | - thermal energy

Question 50

how is energy changed when a kettle has boiled water?

Answer 50

- electrostatic energy | - thermal energy

Question 51

what is the definition of a closed system and what is an example?

Answer 51

- energy can flow in and out - but no mass change - pan boiling water, with lid, no steam can escape

Question 52

how does energy have anything to do with closed systems?

Answer 52

- energy transfers | - no change to total energy

Question 53

how are mechanical processes wasteful? and give example.

Answer 53

- lead to risen temperature - energy stored in less useful ways - light + sound energy from TV absorbed into people rising their temperature

Question 54

how is energy dissipated? example.

Answer 54

- some usefully transferred some dissipated | - TV giving out heat

Question 55

what are some of the ways of reducing unwanted energy transfers?

Answer 55

lubrication- reduces friction, therefore reduces thermal energy insulation- reduces energy transfer by heating, air gaps in walls

Question 56

what are the effects of thermal conductivity?

Answer 56

- how well material transfers energy - metal has a high thermal conductivity - house walls have a low to keep heat in

Question 57

what is the equation for efficiency?

Answer 57

efficiency= useful energy/ total energy

Question 58

how can efficiency be increased?

Answer 58

thermal insulation | lubrication

Question 59

what are the main renewable energy resources?

Answer 59

``` solar cells bio-fuels - animals and pants tidal power wind turbines hydroelectricity ```

Question 60

what are the main non- renewable energy resources?

Answer 60

nuclear fuels | fossil fuels

Question 61

what are some of the pattern and trends with energy use?

Answer 61

- bio mass remained constant - mostly used fossil fuels - huge rise in energy usage - huge rise in population - increase in nuclear power