Motion Flashcards
What does the area beneath a velocity-time graph represent?
The total Displacement in meters
What does the gradient of a velocity-time graph represent?
The Acceleration in meters per second squared
When a projectile is accelerating downwards constantly, what happens to the horizontal component if air resistance is ignored?
It remains constant
If two objects are dropped but one is thrown at an angle, which will reach the ground first? why?
They will reach the ground at the same time because their vertical components are the same (gravity) and their horizontal components don’t change this.
Explain an experiment that could be used to accurately measure a value for g? Include the apparatus and a suitable method.
Apparatus: Steel ball, Electromagnet, Trapdoor, Ruler, Switch, Electronic timer.
1) Turn on electromagnet to attract the steel ball and place it above the trapdoor connected to the timer
2) Measure the displacement (s) between the ball and the trapdoor
3) Release the ball and record the time (t) it takes for the ball to go through the trapdoor
4) Do multiple readings and plot a graph of s against t2
5) Use s=ut+1/2at2, substituting in a for g and having u = 0, meaning s=1/2gt2
6) Rearrange to g=2s/t2, This means the gradient of the graph is equal to g/2 so multiply the value of the gradient of the graph by 2 to get a value for g
What is thinking distance in relation to car stopping distance?
The distance a car travels between the driver seeing the hazard and applying the brakes
What is braking distance in relation to car stopping distance?
The distance a car travels between applying the brakes and coming to rest
What is total stopping distance?
The sum of the thinking and braking distances of a car in an incident or
Total stopping distance = thinking distance + braking distance
How is thinking distance calculated?
reaction time of driver x speed of car
How is braking distance calculated?
E=1/2mv2 and W=Fd
so. .. Fd=1/2mv2
and. .. F=1/2mv2/d
