Newton's Laws

Question 1

what is kinetic energy

Answer 1

Energy that is associated with motion

Ek = mv^2
———
2

When squaring a vector, we obtain the square of the magnitude of the vector, which is then turned scalar

Question 2

what is mechanical energy?

Answer 2

All the energy of an object

ET = Ek + Ep

EPi = EKf

mgh = mv^2
———-
2

gh = v^2
———-
2

Question 3

what is potential energy?

Answer 3

The energy of an object due to the possibility that it could begin to move

EP = mgh

When an object has a greater ability to do work, it has a greater energy.

Changes in height and displacement regarding gravity are always vertical and are relevant to how far they fall and if there is an object in the way

Question 4

scientific and engineering notation

Answer 4

Scientific Notation

2.7 x 10^2 = 270

6 x 10^-3 = 0.006

Engineering Notation
83,201 —-> 83.201 x 103 say 80 K 3 - the power is always powers of 3 (3,9,12 ect)

Question 5

SI UNITS - length, mass,time

Answer 5

length - metre - m

mass - kilogram - kg

time - second - s

Question 6

SI UNITS - quantity of matter and electric current and luminous intensity

Answer 6

quality of matter - mole - mol

electric current - amphere - A

luminous intensity - candela - cd

Question 7

SI units- temperature

Answer 7

temperature - kelvin - K

Kelvin starts at absoulte zero
K = CO + 273.15 K

Question 8

what is the conservation of energy?

Answer 8

Energy cannot be created or destroyed and total energy never changes

ΣEnergyinitial = ΣEnergyfinal

Energy is measured in joules (j)

Question 9

what is a scalar quantity?

Answer 9

a quantity described by magnitude alone

Question 10

what is a vector quantity?

Answer 10

a quantity described by direction and magnitude

if a vector is used, must state direction at the end

Question 11

what is displacement?

Answer 11

how far an object is from the starting point and direction

Question 12

what is energy?

Answer 12

Energy is the ability to do work

Question 13

what is force?

Answer 13

the pull or push on an object that causes it to change velocity

Question 14

what is inertia?

Answer 14

the tendency to remain at rest/the same

Question 15

what is kinetic energy?

Answer 15

energy associated with motion

Question 16

what is momentum?

Answer 16

Momentum is mass in motion and has magnitude and direction (directional - velocity x mass)

P = m v

P- momentum
m - mass
v- velocity

kg/ms-1

Question 17

what is motion?

Answer 17

the change in position

Question 18

what is Newton’s First Law?

Answer 18

The first law is also known as The Law of Inertia

“An object remains at rest (not moving) or continues to move at a constant velocity, (uniform motion in a straight line), unless acted on (for a period of time) by a force (an interaction that will change the motion of an object).

Question 19

what is potential energy?

Answer 19

Energy of an object due to the possibility it could begin to move

Question 20

what is velocity?

Answer 20

the rate of change of displacement (ms-1)

Question 21

collisions

Answer 21

In any closed system, momentum is conserved
If kinetic energy is also conserved, then it has been an elastic collision

∑EK i = ∑Ek f conservation of kinetic energy

Question 22

free body diagrams

Answer 22

a way to repersent the forces acting on a body without the context of its environment

should NOT include:

• other bodies and its enviroment
• internal forces
• forces exerted BY the body

Question 23

friction force

Answer 23

force between two surfaces that are sliding or trying to slide across each other. Always works in the direction opposite to the direction of motion

Question 24

newton’s second law

Answer 24

• requires a knowledge of the net force, in order to find the net acceleration
• holds true for the physical world, but not for the subatomic or relativistic

Question 25

Newton’s third law

Answer 25

The law of action/reaction

all forces between two objects exist in equal magnitude and opposite direction

Question 26

Newton’s 3rd Law

Answer 26

The rate of change of a body’s momentum is directly proportional to the force acting on it

FA = - FB

You cannot have a single force in isolation because all forces are interactions with two bodies, a single force cannot be in isolation.

Question 27

reaction forces

Answer 27

friction, kinetic energy, water resistance, drag

Question 28

system boundaries

Answer 28

can move across a system boundry
system energy matter
can move across a system boundry
system energy matter

open YES YES
closed YES NO
isolated NO NO

Question 29

Newtons 2nd law

Answer 29

The Law of Acceleration

” that the acceleration provided to an object by a kown force is inversley proportional to its mass”

anet = Fnet
m

Question 30

what is normal force?

Answer 30

component of contact force that acts perpendicular to the surface

Question 31

what is an applied force?

Answer 31

force applied to an object by an object or force outside of itself

Question 32

what is a drag force?

Answer 32

an aerodynamic force that opposes an objects motion through fluid eg. air

Question 33

what is impulse?

Answer 33

impulse - change in momentum (momentum and time)

impulse - momentum and time (change in motion)

Δ p = Ft

the evidence for impulse is a change in velocity (speed and direction)

Δ p = mvf - mvi or Δ p = m Δ v or Δ p = m (vf - vi)

Question 34

what is newton’s second law

Answer 34

The rate of change of a body’s momentum is directly proportional to the force acting on it

F = Δp
Δ t 
measured in kgms-2
F= ma 
a = F/m

Question 35

what is net force?

Answer 35

vector sum of all forces acting on an object

Question 36

what is a tension force?

Answer 36

transmitted through rope, strig, wire when pulled by forces acting on opposite sides

Question 37

What is the conservation of momentum?

Answer 37

Momentum is conserved in interactions between objects in a closed system - where matter can move across a system boundary

Total momentum never changes

∑ Pinitial = ∑Pfinal

Question 38

what is weight force?

Answer 38

force due to gravity on mass

Question 39

force

Answer 39

f=ma
mass (kg)/ acceleration /ms2
SI units : N
heavier forces require more force to accelerate

Question 40

acceleration

Answer 40

a = Δ v/ Δ t

acceleration is a change in velocity as a result of impulse