Forces

Question 1

acceleration

Answer 1

rate of change of velocity

Question 2

what does the gradient on a distance time graph show?

Answer 2

velocity

Question 3

what does the gradient and area on a velocity time graph represent?

Answer 3

area- distance travelled
gradient- acceleration

Question 4

what forces are acting on an object in freefall?

Answer 4

only g

Question 5

stopping distance

Answer 5

total distance travelled from when the driver first sees a reason to stop to when the vehicle stops

Question 6

stopping distance equation

Answer 6

thinking distance + breaking distance

Question 7

thinking distance

Answer 7

distance travelled between the moment of realizing to brake and when the breaks are applied

Question 8

thinking distance equation

Answer 8

speed x reaction time

Question 9

braking distance

Answer 9

distance travelled from the moment the break is used and the car comes to a stop

Question 10

what are the 4 most common forces on an object?

Answer 10

weight
normal contact force
tension
friction

Question 11

inertia

Answer 11

an object’s resistance to a change in velocity
(momentum/velocity)

Question 12

friction

Answer 12

a force that opposes motion

Question 13

what are the two types of friction?

Answer 13

contact friction
fluid friction

Question 14

mass

Answer 14

the amount of matter an object has

Question 15

force

Answer 15

the rate of change of momentum
(F=ma)

Question 16

Centre of gravity

Answer 16

the point at which the weight of the object may be considered to act

Question 17

how do you find the centre of gravity of an object?

Answer 17

when applying a force to an object t not at the center of gravity it will rotate
whereas when pushed at its centre of gravity it will be pushed

Question 18

what is the net force of an object when in equilibrium?

Answer 18

0

Question 19

fluid

Answer 19

any substance that flows (eg water,air)

Question 20

what does the magnitude of drag depend on?

Answer 20

speed of the object
cross sectional area of the object
roughness of the object
density of the fluid

(drag force ∝ speed squared)

Question 21

terminal velocity

Answer 21

when the drag force on the object is equal and opposite to its weight (acceleration)

Question 22

the moment of a force

Answer 22

the turning effect of a force about some axis or point

Question 23

what is the principle of moments?

Answer 23

the sum of the clockwise moments is equal to the sum of the anticlockwise moments

Question 24

couples

Answer 24

pair of forces working in opposite directions but not in equilibrium
(they are equal and opposite and they rotate but cause no translation)

Question 25

torque

Answer 25

the moment of a couple

Question 26

density

Answer 26

how much mass per unit volume

Question 27

what is the air pressure at sea level?

Answer 27

100,000 pa

Question 28

Archimedes principle

Answer 28

the upthrust exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces

Question 29

work done

Answer 29

force x distance moved in the direction of the force

Question 30

energy

Answer 30

the capacity to do work

Question 31

what is the principle of energy?

Answer 31

total energy for a closed system remains constant energy cannot be created or destroyed energy is transferred from one store to another

Question 32

what does potential mean in physics?

Answer 32

hidden or stored

Question 33

kinetic energy

Answer 33

energy associated with an object as a result of its motion (KE=1/2 m (v squared)

Question 34

gravitational potential energy

Answer 34

capacity for doing work as a result of an objects position in a gravitational field (GPE=mgh)

Question 35

power

Answer 35

the rate of work done

Question 36

chemical energy

Answer 36

energy contained within the chemical bonds between atoms

Question 37

elastic potential energy

Answer 37

energy stored in an object as a result of reversible change in its shape

Question 38

electrical potential difference

Answer 38

energy of electrical charges due to their position in an electric field

Question 39

nuclear energy

Answer 39

energy within the nuclei of atoms

Question 40

EM energy

Answer 40

energy associated with EM waves stored within oscillating electric and magnetic fields

Question 41

sound energy

Answer 41

energy of mechanical waves due to the movement of atoms

Question 42

thermal energy

Answer 42

the sum of the random potential and kinetic energies of atoms in a system

Question 43

tensile forces

Answer 43

a force that produces an extension

Question 44

compressive forces

Answer 44

a force that shortens (compresses) an object

Question 45

elastic deformation

Answer 45

the object will go to the original shape when the force is removed

Question 46

plastic deformation

Answer 46

when the object has been stretched past its elastic limit and does not go back to its original shape

Question 47

Hooke's law

Answer 47

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

Question 48

what are the 3 forms of loading in alevel physics?

Answer 48

compression tension bending

Question 49

how much an object can extend depends on what factors?

Answer 49

length material tension in wire diameter

Question 50

tensile stress

Answer 50

the force applied per unit cross sectional area of the wire (It’s essentially pressure)

Question 51

stress

Answer 51

an internal force induced in a metal in response to an externally applied force

Question 52

tensile strain

Answer 52

the fractional change in the original length of a wire

Question 53

necking

Answer 53

the point where a material starts to break

Question 54

young's modulus

Answer 54

the ratio of stress to strain of a particular material

Question 55

newton's first law

Answer 55

an object will remain at rest or continue to move with a constant velocity unless acted upon by a resultant force

Question 56

newtons second law

Answer 56

the net force acting on an object is directly proportional to the rate of change of its momentum and in the same direction as the force (net force ∝ rate of change of momentum)

Question 57

newton's third law

Answer 57

when two objects interact, they exert equal and opposite forces on each other

Question 58

momentum

Answer 58

property of a moving object defined as the product of its mass and velocity

Question 59

conservation of momentum

Answer 59

total amount of momentum before is equal to the momentum after the collision

Question 60

what is a perfectly elastic collision?

Answer 60

a Collison where momentum, total energy and total KE are conserved

Question 61

what is a inelastic collision?

Answer 61

a collision where only momentum and total energy is conserved but KE isnt

Question 62

impulse

Answer 62

Change in momentum product of force and time for which this force acts on an object impulse of a force= change in momentum F x change in t = change in P