Dynamics and space Flashcards
Describe Velocity?
Velocity is the change in velocity per unit time, measured in metre per second squared(ms^-2)
What does the term resultant mean?
The resultant is the sum of two or more vectors.
The acceleration of an object is equal to what?
The gradient on its velocity time graph
Describe Force?
Force is a vector. Force is measured in Newtons
What are the effects of forces?
Forces can change the shape, speed or direction of an object.
What does instantaneous speed mean?
The instantaneous speed is the average speed measured over a very short period of time.
Fully describe both a scalar and vector?
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.
What are some Scalar quantities?
Time, Distance, Mass, Speed, Volume, Temperature, Energy
What are some Vector quantities?
Force, Velocity, Acceleration, Displacement
What is Friction?
Friction is a force that opposes motion
State Newtons First Law?
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.
Describe Weight?
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
Describe Mass?
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
What is the gravitational field strength?
This is the weight per unit mass
Measured in newtons per kg (Nkg^-1)
Explain what is meant by balanced forces?
Forces are balanced if they are equal in size but opposite in direction.
Explain Newtons Second Law?
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.
What does work done mean?
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.
State Newtons Third Law?
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
What is a projectile?
A projectile is an object that has been given an initial velocity.
Describe a projectile?
A projectile has a constant velocity in the horizontal direction and a constant vertical acceleration due to gravity.
What is a Satellite?
A satellite is a special projectile
The path it follows is called an orbit
What is a satellites Period?
This is the time it takes for the satellite to orbit the earth once.
this depends on how high the satellite is
What is a geostationary satellite?
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.
What is a light year?
A light year is the distance light travels in a year.
What is the current best estimate for the age of the universe?
13.8 billion years.
