January exam Flashcards
(22 cards)
Velocity
Speed in a certain direction = vector.
Displacement
(distance time graphs)
The distance between the start and the end points of a journey in a straight line (the length of the actual journey).
What do scalar quantities have?
Magnitude, not direction.
Why are forces vector quantities?
Because they have:
- direction
- size (magnitude)
Acceleration (vector quantity)
A measure of how fast velocity is changing.
Momentum
A combination of mass and velocity (a vector)
Examples of vector quantities
- displacement
- velocity
- force
Examples of scalar quantities
- speed
- mass
- energy
- weight
- time
- distance
Instantaneous speed
The speed of a moving object at one moment in time
How do you calculate time?
Distance divided by speed
How do you work out speed?
Distance divided by time
How do you work out distance?
Speed times time
What is the unit for measuring average speed?
Metres per second
How are forces represented?
With force arrows
- size indicates the magnitude
- direction indicates which way the force acts
How do you work out the resultant force?
You add together the forces acting together in the same direction and subtract forces operating in the opposite direction.
What will unbalanced forces do?
Make the object change its speed.
What is mass?
- The quantity of matter in an object (the atoms that make up the object)
- Does not change unless the object changes
- Unit = kilograms/grams (scales)
What is weight?
- The pull of gravity on an object
- A force = vector, meaning it has a direction (towards the earth’s core)
- Unit = Newtons (N)
- force metre
- weigh changes depending on gravitational pull
What is the gravitational field strength on earth?
10 N / kg
What is the formula for calculating weight?
Mass x gravitational field strength
Formula for average acceleration
a = (v-u)/time (s)
u = initial velocity
v = final velocity
How do you work out the gradient in distance time graphs?
Gradient = speed
The speed at any point is equal to the gradient of the line.
