Flashcards in Chapter 3, Motion Deck (17):
Defining equation for speed?
v=x/t (speed = change in distance/change in time).
Which axis is which on a distance-time graph?
time is x-axis, distance is y-axis.
What is given by the gradient of a displacement-time graph?
How do you find the instantaneous speed from a distance-time graph?
Draw a tangent.
What are the vector quantities of distance and speed?
Displacement and velocity.
Defining equation for acceleration?
a=v/t (change in velocity/change in time).
How do you find the total displacement from a velocity-time graph?
Find the area under the curve.
What do the letters in the suvat equations represent?
s=displacement, u=initial velocity, v=final velocity, a=acceleration, t=time taken.
Suvat equation including a,v,u and t?
a=(v-u)/t, derived from defining equation for acceleration
Suvat equation including s,u,a and t?
s=ut+(1/2)at^2, from area of trapezium from velocity-time graph. Also s=vt-(1/2)at^2 is also a valid equation.
Requirements for suvat equations to apply?
Acceleration is constant for motion in a straight line.
Suvat equation including s,u,v and t?
s=(1/2)(u+v)t from the average velocity * time.
Suvat equation including s,u,v and a?
What factors affect stopping distance?
Thinking distance and breaking distance.
How do you calculate thinking distance when stopping a car?
Thinking distance = speed*reaction time
What methods are there for determining acceleration due to gravity (g)?
Electromagnet and trapdoor:
An electromagnet holds a steel ball above a trapdoor, when the current is switched off the ball falls breaking the contact in the trapdoor stopping the timer.
Use two sets of double light gates to determine change in velocity
By taking pictures of a falling object at small regular intervals you can measure how much more the ball falls each time and use this to measure g.