Section 17: Motion, Forces And Conservation Of Energy Flashcards
What is a vector quantity
Something that has magnitude and direction
What is magnitude
Size
What is a scalar quantity
Something that only has magnitude
What quantity is force
Vector
What quantity is speed
Scalar
What quantity is temperature
Scalar
What quantity is time
Scalar
What quantity is momentum
Vector
What quantity is weight
Vector
What quantity is energy
Scalar
What quantity is velocity
Vector
What quantity is acceleration
Vector
What quantity is mass
Scalar
What quantity is displacement
Vector
What quantity is distance
Scalar
What are examples of vector quantities
- force
- velocity
- displacement
- weight
- acceleration
- momentum
What are examples of scalar quantities
- speed
- temp
- distance
- time
- mass
- energy
Distance
How far an object has moved, it is a scalar quantity so it doesn’t involve direction
Displacement
It is a vector quantity so it measures the distance and direction in a straight line from the objects starting point to the finishing point.
So if you walk 5m north then 5m south, the displacement is 0m but the distance is 10m
Speed
How fast you’re going with no regard to the direction
Velocity
The speed in a given direction
Equation for distance travelled
Distance travelled = speed x time
Speed of walking
1.4 m/s
Average speed of running
3 m/s
Average speed of Cycling
5.5 m/s
What is acceleration
The change in velocity in a certain amount of time
How quickly you’re speeding up
How to work out average acceleration
a= (v-u)/t
a= acceleration
v = final velocity
u= initial velocity
t = time
What is deceleration
The negative acceleration, if something slows down the change in velocity is negative
How to work out constant acceleration
V^2 - u^2 = 2 X a X x
A= acceleration
x = distance
Distance/time graphs
tells you how far something has travelled
What do the different parts of the distance/time graphs show
- gradient (slope)= at any point, shows us the speed of an object
- flat sections= where it’s stopped
- the steeper the graph the faster the speed
- curves = represent the acceleration, if the curve is steep it means it’s speeding up.
- a levelling off curve means it’s slowing down
How to work out the speed of an object from a distance/time graph
Change in the vertical/change in the horizontal
What is a tangent
A line that is parallel to the curve at that point
What do the different parts of a velocity/time graph show
Gradient = acceleration
Flat section = steady speed
Steep line = greater acceleration
Uphill sections (/) acceleration
Downhill () deceleration
Curve = changing acceleration
How to calculate the distance travelled on a time/velocity graph
The area under the graph
Newton’s first law
If the resultant force on a stationary object is 0, the object will remain stationary.if. The resultant dove on a moving object is 0, it’ll just carry on moving at the same velocity
Newton’s second law
F = m x a
