ODU(part 2)

Question 1

What is a projectile

Answer 1

A projectile is any object which freely accelerates due to gravity whilst moving forward at the same time.

Question 2

What are the 2 main types of projectiles

Answer 2

horizontal and angled

Question 3

What 2 componenets are projectiles made up of

Answer 3

projectiles are made up of horizontal and vertical components which act independently.

Question 4

Describe the horizontal component of a projectile

Answer 4

Constant velocity, no acceleration

Question 5

Describe the vertical component of a projectile

Answer 5

constant downwards acceleration due to gravity, where a = 9.8 ms^-2

Question 6

What is the formula for the horizontal component of velocity in an angled projectile

Answer 6

uh = ucos0

uh = initial horizontal speed
0 = angle of projectile
u = initial speed of projectile

Question 7

What is the formula for the vertical component of velocity in an angled projectile

Answer 7

Uv = usin0

uv = initial vertical velocity
0 = angle of projectile
u = initial speed of projectile

Question 8

The moon is a …

Answer 8

natural satellite

Question 9

The ISS is an…

Answer 9

artificial satellite

Question 10

What does gravitiation force between two objects depend on

Answer 10

the two masses

distance between their centres

Question 11

State newtons law of gravitation

Answer 11

F = Gm1m2/r^2

m1 and m2 are masses of the two objects in kg
r is the distance between the centres of the objects.
G is the universal constant of gravitation.

Question 12

State the universal constant of gravitation

Answer 12

G = 6.67*10^-11 Nm^2kg^-2 (given on data sheet)

Question 13

the gravitational force between an object and a planet is its []

Answer 13

weight

Question 14

What is a frame of reference

Answer 14

How you describe the motion of an object depends on how you observe it

Question 15

What is an inertial reference frame

Answer 15

Simply two places that are moving at constant speeds relative to one another.

Question 16

What is an absolute reference frame

Answer 16

A unique, universal frame of reference from which everything could be defined or measured. Einstein proved no such reference frame exists.

Question 17

What are einsteins 2 postulates (assumptions)

Answer 17

1) observers moving at constant speed relative to one another (inertial frames) will observe the same laws of physics.

2) the speed of light in a vacuum is the same for all observers regardless of their motion relative to the light source.

Question 18

What is time dilation

Answer 18

Time dilation is the difference in a time interval as measured by a stationary observer and a moving observer.

Question 19

State the dilated time formula

Answer 19

t’ = t/ (√(1-(v/c)^2))

where t is proper time
t’ is dilated time
v is the velocity of the object relative to a rest frame
c is the speed of light in a vacuum

Question 20

Define proper time

Answer 20

Proper time is the time measured in the frame in which the clock is at rest relative to the event. The time will always be shorter in the rest frame.

Question 21

Define dilated time

Answer 21

Dilated time is the time measured on a clock that is moving with a constant velocity relative to you. The time will be longer so the clock is seen to be running slow.

Question 22

What is length contraction

Answer 22

Length contraction is a difference in the length of an object as measured (parallel to the direction of travel) by a stationary observer and a moving observer.