forces and motion s1

Question 1

eq for speed

Answer 1

speed = distance ÷ time

Question 2

is speed vector or scalar

Answer 2

scalar

Question 3

is distance vector or scalar

Answer 3

scalar

Question 4

units for speed

Answer 4

m/s

Question 5

eq for acceleration

Answer 5

acceleration = change in velocity ÷ time

Question 6

units for acceleration

Answer 6

m/s2

Question 7

is acceleration vector or scalar

Answer 7

vector

Question 8

straight lines on distance time graphs

Answer 8

steady constant speed

Question 9

steep line on distance time graphs

Answer 9

low speed

Question 10

horizontal line on distance time graphs

Answer 10

stationary

Question 11

curve on distance time graphs

Answer 11

acceleration

Question 12

straight lines on velocity time graphs

Answer 12

steady constant acceleration

Question 13

horizontal line on velocity time graphs

Answer 13

constant speed

Question 14

how to find distance on velocity time graph

Answer 14

area under the line

Question 15

are forces vector or scalar

Answer 15

vector

Question 16

eq for force

Answer 16

force = mass x acceleration

Question 17

what happens when an unbalanced force acts on an object

Answer 17

the object accelerates

Question 18

what happens when an balanced force acts on an object

Answer 18

it will remain at rest or continue to move and the same speed

Question 19

how does a larger net force affect the acceleration

Answer 19

it increases it

Question 20

how can acceleration be measured (in class)

Answer 20

using light gates and a data logger

Question 21

eq for weight

Answer 21

weight = mass x g

Question 22

what is friction

Answer 22

a force that opposes motion

Question 23

describe terminal velocity

Answer 23

when the air resistance acting on an object becomes equal to the thrust, this means there is no acceleration and it cannot go faster

Question 24

eq for momentum *

Answer 24

momentum = mass x velocity

Question 25

what is the principle of conservation of momentum

Answer 25

the total momentum before an event (collision) is equal to the total momentum after the event - provided there are no external forces acting

Question 26

what does momentum depend on

Answer 26

- size of force | - time the force is in contact with the object

Question 27

what eq links momentum and force

Answer 27

force = change in momentum ÷ time

Question 28

how does a rubber floor prevent less injury than a concrete floor

Answer 28

if someone falls on rubber the surface deforms and the collision time is increased - the momentum change takes place over a longer time and the force is reduced

Question 29

eq for moment

Answer 29

moment = force x perp distance from pivot

Question 30

where does the weight of a body act

Answer 30

through its centre of gravity

Question 31

what is a moment

Answer 31

the turning force on an object that causes it to rotate

Question 32

what is the principle of moments *

Answer 32

total anticlockwise moment + total clockwise moment for equilibirum

Question 33

what is hookes law

Answer 33

extension is directly proportional to force, provided the elastic limit hasn't been exceeded

Question 34

what is elastic behaviour

Answer 34

when the force is removed the spring goes back to its original length

Question 35

what is plastic behaviour

Answer 35

when the force is removed the sting is permanently stretched

Question 36

what do gravitational forces do

Answer 36

cause things to orbit around other things | e.g. (planets around sun, moons around planets)

Question 37

describe the orbit of a comet

Answer 37

elliptical

Question 38

eq for orbital speed

Answer 38

2 x π x orbital radius ------------------------------ time period