P2 - Forces Flashcards
How to measure the distance?
Use a ruler
How to measure time?
Use a stopwatch
For accuracy - use light gates
What is a accurate way to measure distance and how does it work?
Ultrasound
There is a motion sensor that emits ultrasound wave.
It times how long it takes for the pulse to travel to an object and back again.
Use the distance = speed * time to calculate distance
What is uniform motion?
Speed does not change
Distance (m) = speed (m/s) * time (s)
What is non uniform motion?
Speed changes
Average speed (m/s) = total distance (m) / total time (s)
How to convert miles into metres?
1 mile = 1609 metres
What is a vector?
Quantity that has direction and magnitude
E.g. forces
Length of the arrow tells the magnitude and direction that the arrowhead points is the direction
What is a scalar?
Has a magnitude but no direction
E.g. time
What is distance?
How far you’ve travelled (scalar quantity)
What is displacement?
Distance from a point in a particular direction (vector quantity)
What is speed?
How fast something is going (scalar)
What is velocity?
How far something’s going in a given direction (vector)
What is the formula for acceleration?
Acceleration (m/s^2) = change in velocity (m/s) / time (s)
What is the acceleration due to gravity on earth?
9.81 m/s^2
What does a graph of distance against time mean?
Tells you the speed of an object on its journey
Horizontal line - stationary , not moving
Diagonal line - object moving at steady speed
Curved line - moving at changing speed
