Section 1 Flashcards
What is gravity?
The force of attraction between all masses.
What is weight measured in?
Newton.
How can you reduce friction?
Put a lubricant such as oil or grease between the layers.
What is free fall?
When an object is falling with no driving force acting on it.
If you are going at a steady speed, there must be…
…zero resultant force.
What will an unbalanced force always produce?
Acceleration.
What is the difference between vectors and scalars?
Vectors have size and direction, scalar quantities only have size.
What is a moment?
The turning effect of a force.
Where is the centre of gravity of an object?
The centre of gravity hangs directly below the point of suspension.
What does Hooke’s Law say?
Extension is proportional to force.
What happens if you stretch an object past its elastic limit?
The material will become permanently stretched, and when the force is removed, the material will be longer than at the start.
What are comets?
Small lumps of icy rock which orbit the Sun.
What is a galaxy?
A large collection of stars.
How are moon and artificial satellites held in orbit>
Gravity.
Why does a comet travel faster when it is nearest to the sun?
The increased pull of gravity makes it speed up the closer it gets to the sun.
