Our dynamic universe

Question 1

what are the equations of motion used for?

Answer 1

Acceleration
Projectile Motion
and any other movement question

Question 2

F=ma is used when?

Answer 2

Unbalanced forces e.g. Friction, Air resistance

Tension

Question 3

How do you calculate momentum?

Answer 3

p=mv

Question 4

How to I find resultant forces?

Answer 4

Trigonometry (the hypotenuse is always the resultant force)

Question 5

State Newtons 3 laws of motion?

Answer 5

1. An object will remain at a constant velocity unless acted upon by an unbalanced force.
2. The acceleration of an object is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
3. Every action has an equal and opposite reaction

Question 6

When do I use a vector diagram

Answer 6

Finding forces in two directions
Finding resultant force
Finding resultant speed
(You see a slope, think triangle)

Question 7

What relationships can be used to calculate work done?

Answer 7

Ew =Fd
Ek = 1/2mv²
Ep=mgh

Question 8

define impulse?

Answer 8

Change in momentum

Ft = mv − mu

Question 9

What is frictional force?

Answer 9

the unbalanced force (the difference between the other two forces

Question 10

How do I calculate impulse after a collision?

Answer 10

calculate momentum before & after collision
take away one value from the other
plug into Ft= mv - mu

Question 11

What is Power

Answer 11

E/t

Question 12

What is the difference between t and t’

Answer 12

t is proper time and t’ is time from the observers frame of reference
t < t’

Question 13

Difference between l and l’

Answer 13

l is proper length, l’ is length from an observers frame of reference
l > l’

Question 14

Calculate observed frequency

Answer 14

fₒ =fₛ (v/v+or-vₛ)

Question 15

z=

Answer 15

redshift

Question 16

Hₒ=

Answer 16

Hubble’s constant

Question 17

p=

Answer 17

momentum

Question 18

Area under displacement time graph

Answer 18

velocity

Question 19

Area under velocity time graph

Answer 19

acceleration

Question 20

what is terminal velocity

Answer 20

Maximum speed of an object, where all forces acting upon the object become equal

Question 21

State the conservation of momentum

Answer 21

Momentum will remain the same before and after a collision provided that it isn’t acted upon by an unbalanced force.

Question 22

inelastic and elastic

Answer 22

Inelastic is when external forces are acting upon the collision such as friction. Elastic collisions are free of any external forces.

Question 23

Area under force time graph

Answer 23

impulse

Question 24

speed of light in a vacuum

Answer 24

is the same for all observers

Question 25

Causes shifts in the wavelengths of sound and light

Answer 25

the Doppler effect

Question 26

moving away from us, longer wavelengths

Answer 26

Redshift

Question 27

Moving towards us, shorter wavelengths

Answer 27

Blueshift

Question 28

estimation of the mass of galaxies

Answer 28

dark matter

Question 29

Accelerating expansion of the Universe

Answer 29

Dark energy

Question 30

Peak wavelength shorter

Answer 30

Hotter object

Question 31

Peak wavelength longer

Answer 31

Colder object

Question 32

fs=

Answer 32

Source frequency

Question 33

fo=

Answer 33

Observed frequency

Question 34

Recessional velocity of a galaxy

Answer 34

V=Hod