Flashcards in Chapter 3, Motion Deck (17):
1
Defining equation for speed?
v=x/t (speed = change in distance/change in time).
2
Which axis is which on a distance-time graph?
time is x-axis, distance is y-axis.
3
What is given by the gradient of a displacement-time graph?
Velocity.
4
How do you find the instantaneous speed from a distance-time graph?
Draw a tangent.
5
What are the vector quantities of distance and speed?
Displacement and velocity.
6
Defining equation for acceleration?
a=v/t (change in velocity/change in time).
7
How do you find the total displacement from a velocity-time graph?
Find the area under the curve.
8
What do the letters in the suvat equations represent?
s=displacement, u=initial velocity, v=final velocity, a=acceleration, t=time taken.
9
Suvat equation including a,v,u and t?
a=(v-u)/t, derived from defining equation for acceleration
10
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.
11
Requirements for suvat equations to apply?
Acceleration is constant for motion in a straight line.
12
Suvat equation including s,u,v and t?
s=(1/2)(u+v)t from the average velocity * time.
13
Suvat equation including s,u,v and a?
v^2=u^2-2as.
14
What factors affect stopping distance?
Thinking distance and breaking distance.
15
How do you calculate thinking distance when stopping a car?
Thinking distance = speed*reaction time
16
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.
Light gates:
Use two sets of double light gates to determine change in velocity
Taking pictures:
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.
17