Our Dynamic Universe

Question 1

Definition of acceleration

Answer 1

The rate of change of velocity (ms-2)

Question 2

Newtons 1st law

Answer 2

When the forces acting on an object are balanced it remains at rest or a constant speed

Question 3

Newtons 2nd law

Answer 3

When an unbalanced force is applied to an object the acceleration of the object is directly proportional to the unbalanced force and inversely proportional to its mass

Question 4

Newtons 3rd law

Answer 4

For every action there is an equal and opposite reaction

Question 5

What happens is the velocity of an object increases?

Answer 5

The frictional force also increases

Question 6

Terminal velocity

Answer 6

When an object falls at a velocity where the forces on it become balanced

Question 7

Principle conservation of energy

Answer 7

Energy cannot be created or destroyed

Question 8

Law of conservation of momentum

Answer 8

Total momentum before a collision is equal to to the total momentum after a collision in the absence of external forces

Question 9

What is conserved in an elastic collision?

Answer 9

Momentum and kinetic energy are conserved

Question 10

What is conserved in an inelastic collision?

Answer 10

Momentum is conserved and kinetic energy is not conserved

Question 11

How do u determine whether a collision is elastic or inelastic

Answer 11

Calculate the total energy before and after the collision

Question 12

The area under a force-time graph is equal to….

Answer 12

Impulse

Question 13

Horizontal motion equation

Answer 13

S=vt

Question 14

Vertical motion equation

Answer 14

V=u + at

Question 15

2 theory’s of special relativity

Answer 15

1. When two observers are moving at constant speeds relative to one another, they will observe the same laws of physics
2. The speed of light (in a vacuum) is the same for all observers

Question 16

Time dilation….

Answer 16

Increase in time of events on an object moving relative to an observer

Question 17

Length contraction….

Answer 17

Decrease in length of an object moving relative to an observer

Question 18

When a source moves towards an observer…..

Answer 18

( - )

Question 19

When a source moves away from an observer….

Answer 19

( + )

Question 20

Redshifted….

Answer 20

Light from objects moving away from us are shifted to longer wavelengths

Question 21

Blue shifted….

Answer 21

Light from objects moving towards us are shifter to shorter wavelenghts

Question 22

What is dark energy?

Answer 22

The unknown force acting against gravitational attraction

Question 23

4 pieces of Evidence for the Big Bang

Answer 23

1. Hubbles law
2. Cosmic microwave background radiation
3. Olbers paradox
4. Proportions of hydrogen, helium and other elements

Question 24

Black-body radiation curve

Answer 24

A graph of the emitted radiation against wavelength has a characteristic shape

Question 25

At all wavelengths…

Answer 25

The radiation emitted per unit surface area per unit time for hotter objects is greater than that for coller objects

Question 26

Percentage uncertainty formula

Answer 26

Uncertainty\ value x 100

Question 27

Impulse equation

Answer 27

kgms -1