P2 - Gravity Flashcards
What is weight?
The force of gravity acting on the mass measured in Newtons (N)
What is the strength of gravity on Earth?
10N per kg in GCSE
What is mass?
The amount of matter there is in a body which is measured in grams (g)
How do you calculate weight?
Mass * gravitational field strength (10 N/kg)
What does gravitational force cause on a planet?
All things accelerate towards the centre of the planet at the same acceleration
For Earth, acceleration is 10m/s^2
What is terminal velocity?
When the force of gravity and the force of the air resistant of a falling object are equal, the object is travelling at terminal velocity
Why do we reach terminal velocity?
When an object falls, the force of gravity is higher than the force of air resistance (friction) slowing them down so they accelerate but as the speed increases, the air resistance increases and the acceleration slows until the force of gravity and air resistance are equal so the object will travel at a constant velocity
What 2 factors affect terminal velocity?
If the area of the face going against the air resistance is high then there will be more air resistance
If the mass is higher, then the weight will be higher so more air resistance is needed to reach terminal velocity
Why does a feather have such a low terminal velocity?
It has a very wide surface area
It has a low mass
How do cars make use of our knowledge of air resistance?
They are made more aerodynamic which means that air flows very easily and smoothly past them minimising air resistance
This allows the “terminal velocity” to be higher because there is less air resistance
