Dynamics and space

Question 1

Describe Velocity?

Answer 1

Velocity is the change in velocity per unit time, measured in metre per second squared(ms^-2)

Question 2

What does the term resultant mean?

Answer 2

The resultant is the sum of two or more vectors.

Question 3

The acceleration of an object is equal to what?

Answer 3

The gradient on its velocity time graph

Question 4

Describe Force?

Answer 4

Force is a vector. Force is measured in Newtons

Question 5

What are the effects of forces?

Answer 5

Forces can change the shape, speed or direction of an object.

Question 6

What does instantaneous speed mean?

Answer 6

The instantaneous speed is the average speed measured over a very short period of time.

Question 7

Fully describe both a scalar and vector?

Answer 7

A Scalar quantity is fully described by stating its magnitude only(size).
A Vector quantity is fully described by stating both its magnitude and direction.

Question 8

What are some Scalar quantities?

Answer 8

Time, Distance, Mass, Speed, Volume, Temperature, Energy

Question 9

What are some Vector quantities?

Answer 9

Force, Velocity, Acceleration, Displacement

Question 10

What is Friction?

Answer 10

Friction is a force that opposes motion

Question 11

State Newtons First Law?

Answer 11

A stationary object will remain at rest or a moving object will remain with a constant velocity unless an unbalanced force acts on the object.

Question 12

Describe Weight?

Answer 12

Weight is a force.
Weight is the gravitational pull of a planet on an object
Weight is a vector quantity
Its direction is towards the centre of a planet

Question 13

Describe Mass?

Answer 13

Mass is the amount of matter in an object
Mass is measured in kg
Mass is a scalar quantity
The mass of an object does not change

Question 14

What is the gravitational field strength?

Answer 14

This is the weight per unit mass

Measured in newtons per kg (Nkg^-1)

Question 15

Explain what is meant by balanced forces?

Answer 15

Forces are balanced if they are equal in size but opposite in direction.

Question 16

Explain Newtons Second Law?

Answer 16

F=ma
Force = mass x acceleration

1 Newton is the force which produces an acceleration of 1ms^-2 when acting on a mass of 1kg.

Question 17

What does work done mean?

Answer 17

Work done means energy transferred
We say that work is done when a force is applied to an object which then moves a certain distance in the direction of the force.

Question 18

State Newtons Third Law?

Answer 18

For every Force there is an opposite and equal opposite reaction force

OR

If A exerts a force on B, B exerts an equal and opposite force on A

Question 19

What is a projectile?

Answer 19

A projectile is an object that has been given an initial velocity.

Question 20

Describe a projectile?

Answer 20

A projectile has a constant velocity in the horizontal direction and a constant vertical acceleration due to gravity.

Question 21

What is a Satellite?

Answer 21

A satellite is a special projectile

The path it follows is called an orbit

Question 22

What is a satellites Period?

Answer 22

This is the time it takes for the satellite to orbit the earth once.
this depends on how high the satellite is

Question 23

What is a geostationary satellite?

Answer 23

A geostationary satellite is a satellite that takes 24 hours to orbit above the equator and appears to stay in the same place above earth.
It completes one orbit in the same time it takes the earth to rotate once.

Question 24

What is a light year?

Answer 24

A light year is the distance light travels in a year.

Question 25

What is the current best estimate for the age of the universe?

Answer 25

13.8 billion years.