Motion for Constant Acceleration
Equations of Motion for Constant Acceleration
In this lesson the students are shown how to use a velocity-time graph to develop the equations of motion for constant acceleration.To give the students confidence, they are sometimes asked to share ideas with a partner.
We can use a velocity-time graph to find some equations that hold for a body moving in a straight line with constant acceleration.
velocity (ms-
1)
time (s)
u
v
t0
Suppose when the time is 0 . . .
At any time, t, we let the velocity be v.
the velocity is u.
Ans: The gradient gives the acceleration.
Remind your partner how to find acceleration from a velocity-time graph.
Constant acceleration means the graph is a straight line.
We can use a velocity-time graph to find some equations that hold for a body moving in a straight line with constant acceleration.
velocity (ms-
1)
time (s)
u
v
t
a = v - u t
So,
v - u
0
Suppose when the time is 0 . . . the velocity is
u.
t
From this equation we can find the value of any of the 4 quantities if we know the other 3.
At any time, t, we let the velocity be v.
Constant acceleration means the graph is a straight line.
a = v - u t
a t = v - u
v = u + a
t
Multiplying by t: u + a t = v
We usually learn the formula with v as the “subject”.
The velocity, u, at the start of the time is often called the initial velocity.
Top Related