Topic 1 - Motion in the universe

Question 1

Equations

Answer 1

average speed = distance ÷ time
v = d/T
Weight = mass x gravitational field strength
W = m x g
Orbital speed = (2 x pie x R) ÷ orbital time
v = (2 x pie x r) ÷ T

Question 2

Why does gravitational field strength vary?

Answer 2

Gravitational field strength varies depending on the mass it is also different on other planets, e.g the earth and the moon

Question 3

Universe

Answer 3

The universe is a large collection of billons of galaxies

Question 4

Galaxy

Answer 4

A galaxy is a large collection of billions of stars

Question 5

Solar system

Answer 5

I’ll solar system is the Milky Way galaxy

Question 6

Explain that gravitational force in the solar system

Answer 6

Closest moon orbit planets , cause planets to orbit the sun, causes artificial satellite to orbit earth, causes comets to orbit the sun

Question 7

Velocity

Answer 7

Velocity is speed in a given direction.
When a velocity is changing force is given off

Question 8

Mass of an object?

Answer 8

The mass of an object is a measure of how much matter it actually contains, and it does not change unless a part of the object is physically removed.

Question 9

Weight of an object…

Answer 9

The weight of an object is the force acting on the object due to the gravitational field it is in.

Question 10

Mass and weight on earth and the moon

Answer 10

Earth: object of mass of 1kg would have a weight of 10N because its gravitational field strength is 10N/kg
Moon: object of mass of 1kg would have the weight of 1.6N because its gravitational field strength is 1.6N/kg

Question 11

Mass and weight

Answer 11

MASS NEVER CHANGES NO MATTER WHERE IT IS ALTHOUGH WEIGHT DOES DEPENDING ON THE GRAVITATIONAL FORCE

Question 12

Force of object when being dropped…

Answer 12

The weight of an object is the force that causes it to accelerate towards the ground when it is dropped.

Question 13

Circular motion: speed vs velocity

Answer 13

It is possible for a body moving in a circle to be travelling at constant speed yet have a changing velocity. This is due to the unbalanced force. Whenever an unbalanced force acts, a body will accelerate, i.e .its velocity will change.

Question 14

Centripetal force

Answer 14

Any body moving in a circle must have a force acting on it which is perpendicular to the direction of travel, causing it to constantly change direction. This unbalanced force acting towards the centre of the circle is referred to as the centripetal force. It can be provided by any number of forces e.g. gravitational pull, tension, lift, and friction.

Question 15

Orbits

Answer 15

When objects are in orbit around a planet (or star), they are moving in a circle due to the centripetal force of the planet acting on them. The closer they are, the greater the force acting, as the gravitational field strength is greater closer to the planet. This means that they will be orbiting at higher Speeds if they are closer to the planet. This is why planets which are further from the sun have much longer orbital periods (time taken to complete one orbit). Not only do they have to travel further, but they are moving more slowly.

Question 16

Orbital Period

Answer 16

The time it takes the planets and comets to travel around the Sun varies enormously. The time taken for an object to orbit the Sun is known as its orbital period.

Question 17

Gravitational force acting as a centripetal force

Answer 17

The gravitational force between two objects of constant mass is inversely proportional to the square of the distance between them. This means that if the distance is doubled, the gravitational force is quartered.

Question 18

Satellites

Answer 18

A satellite is any object that orbits another object. Satellites can be natural or artificial. The moon is an example of a natural satellite which is kept in orbit by the Earth’s gravitational force

Question 19

Gradient

Answer 19

Gradient and velocity are ALWAYS the same.
Gradient = y axis
——–
x axis