Chapter 9 Constant Acceleration - Year 1 Flashcards
On a velocity time graph what does a horizontal line represent?
A particle is moving at a constant motion
On a velocity time graph what does the gradient represent?
The acceleration of the particle
On a velocity time graph what does a downward sloping straight line represent?
Constant deceleration
On a velocity time graph what does what does the distance underneath the graph represent?
Displacement
How do you find the displacement of an object when a velocity time graph has a negative section?
You subtract the negative bit as it is negative displacement meaning that the particle is getting closer to the origin
On a velocity time graph how do you calculate the total distance?
You add up the area underneath the graph. You also treat any negative area as positive
When do you use SUVAT equations?
When there is CONSTANT ACCELERATION
What is the first constant accelerations SUVAT equation?
v=u+at
What is the fith constant accelerations SUVAT equation?
s= 0.5(u+v)t
What is the forth constant accelerations SUVAT equation?
v^2=u^2+2as
What is the second constant accelerations SUVAT equation?
s=ut+0.5at^2
What is the third constant accelerations SUVAT equation?
s=vt-0.5at^2
What is unique about the constant acceleration SUVAT equations?
How can this be used to out advantage?
Each SUVAT equation is missing 1 variable
This means that we only need 3/5 of the variable to use SUVAT
What does SUVAT stand for?
s - displacement
u - initial velocity
v - final velocity
a - acceleration
t - time
How do you solve a standard constant acceleration formulae question?
What about if they is a part b? Why?
You write SUVAT down the side of you page and fill in the values.
Put a ? next to the value that you want to work out
Find the correct SUVAT equation and write it down
Fill in your values and find the missing variable and solve for it
If there is a part b you will be able to use any of the SUVAT equations.
You should use the equation which doesn’t have the value that you worked out in it (so if your value is wrong you don’t loose 2 marks only 1)
Using constant acceleration SUVAT equations how do you work out the distance until 1 car overtakes a different car?
Write SUVAT twice down your page and fill in what you know
When 1 car overtakes the other their displacement will be the same so you can say s=s
If the question tells you that 1 car leaves latter than another you say that car b’s time is t-(time specified)
You can then find the variable s in terms of t (or another variable)
You then know that s=xt and you can therefore for car a.
You do the same for car b but you substitute xt in for s
You solve for t
You then put in your value for t (for car b) into your equation (t-(take taken) to find the real value for t (one value may be negative and therefore you know that it can’t be that one)
Vcbihceijnijbijbihcecce
On a displacement time graph what does a horizontal line represent?
The particle is stationary
On a displacement time graph what does the gradient represent?
The velocity of the particle
On a displacement time graph what does a curved line represent?
Acceleration of deceleration
On a displacement time graph how do you calculate velocity?
(Distance from the starting point) ÷ Time
On a displacement time graph how do you calculate speed?
(Total distance traveled) ÷ Time
Can speed be negative?
No
What is gravity measured in?
g
What is the value or gravity?
Depends on your positive direction but normally -9.8
What are the 2 often mistake made in exams about gravity?
Making gravity positive when it should be negative
The questions says assume that gravity is 10g
When do you use SUVAT equations?
When acceleration is constant
Gravity is constant
