Motion Flashcards
Scalar quantity
A quantity that only a magnitude
Vector quantity
A quantity with both a magnitude and direction
List scalar quantities
Speed, mass, distance, time, energy, temperature
List vector quantities
Velocity, force, displacement, acceleration, momentum
What is distance, its symbol and units?
- distance = how far an object has traveled with no regard to direction
- symbol = d
- units = meters (m)
What is displacement, its symbol and units?
- displacement = the distance an object has traveled in a certain direction
- symbol = s
- units = meters (m)
What is speed, its symbol and units?
- speed = a measure of how fast an object is travelling
- symbol = s
- units = meters per second (m/s)
Formula for average speed
Average speed = total distance/ total time
What is stopping distance?
Total distance travelled during the time it takes for the vehicle to come to a stop
What is stopping distance consisted of?
Thinking distance and braking distance (in that order!)
What is thinking distance?
Distance travelled during the time it takes for the driver to react
What is braking distance?
Distance travelled whilst the brakes are being applied
Stopping distance formula
Stopping distance = thinking distance + braking distance
Do factors affecting TD affect the driver or the vehicle?
Driver
Do factors affecting BD affect the vehicle or the driver?
Vehicle
Factors affecting thinking distance
- Speed of the car
- drugs + alcohol
- tiredness
- some medications
- caffeine
Factors affecting braking distance
- speed of the car
- icy/wet roads (reduce traction)
- old worn tires (reduce traction)
- overloaded cars (stopping power has to increase so it will take longer to stop)
What does stationary look like on D-T graphs?
Gradient = 0 , horizontal line
What does moving forward look like on D-T graphs?
Positive gradient, upwards slope
What does moving backwards look like on Đ-T graphs?
Neagtive gradient, downwards slope
What does in front/ behind the starting point look like on D-T graphs?
- in front = above x-axis
- behind = below x-axis
What does moving fast look like on D-T graphs?
Steep gradient
What does moving slow look like on D-T graphs?
Shallow gradient
What does constant speed look like on a D-T graph?
Straight line
What does acceleration/deceleration look like on D-T graphs?
Curved line
What is gradient equivalent to on D-T graphs?
Speed
Gradient formula
Change in Y / change in X
Describe the investigating speed experiment
- roll a marble down a ramp with a clamp and stand attached to it
- record time taken for marble to roll down the ramp
- measure the length of the ramp
- divide total distance of ramp by total time taken to obtain average speed of marble
- repeat again with altered height in even increments
Constant velocity on V-T graph
Horizontal line
Acceleration on V-T graph
equivalent to the gradient
Deceleration on V-T graph
Negative gradient
Positive velocity V-T graph
Above x-axis
Negative velocity on V-T graph
Below x-axis
What is gradient equivalent to on a V-T graph?
Acceleration
How do you find distance travelled on a V-T graph?
Use the ‘counting squares method’ and find the area under the graph
- find the area of one square
- count the number of squares
- multiply the values together
OR use the formula s = 1/2(v+u)t
Average velocity formula
Displacement/ time OR v + u / 2
Define acceleration
The rate of change in velocity, meaning that an object’s velocity will increase by x meters per second, every second
Acceleration units
Meters per second squared (m/s2)
Deceleration
Deceleration is slowing down, basically negative acceleration. So if an object is decelerating, its acceleration is always negative as the final velocity will always be smaller than its initial one
Acceleration formula
a = v - u / t
