BHS -> Staff -> Mr. Stanbrough -> Physics -> Mechanics -> Kinematics -> Using v = v_{o} + at -> this page
A car, initially at rest, begins to accelerate at 4.5 m/s^{2}. How fast, in m/s, will it be going in 5.0 seconds?
Step 1 - Understand the problem. (Same as before...)
Step 2 - Translate into physics: (Same as before...)
v_{o} = 0 m/s
a = 4.5 m/s^{2}
v = ?
= 5.0 s
Step 3: Find a kinematics equation: Here's the plan - we could use the equation to solve the problem, but we don't know . Wait! we have that we can use to find .
Step 4 & 5 - Substitute & Solve:
, but we don't know
Step 6 - Report the answer: (Same as before...)
The car will be going 23 m/s in 5.0 seconds.
Note that this is a 2-step solution, which requires a little more thinking than using the equation , but if this method appeals to you, by all means use it.