If an object accelerates from rest, what will its velocity be after 12.3 s if it has a constant acceleration of 4.6 m/s2?

Answer 1

In order to solve any kinematics problem, we need 3 pieces of information from this list:

1. initial velocity vi
2. final velocity vf
3. time t
4. acceleration a
5. displacement x or y

From there, we will pick through our kinematic equations and choose the one that includes all 3 of our known variables along with the 1 unknown we are looking to find.

In this problem, we are given:

“from rest” —> tells us initial velocity vi = 0m/s

“After 12.3 seconds” —> tells us our time is t = 12.3 sec

”Acceleration of 4.6 m/s^2 —> tells us a = 4.6 m/s^2

”what will our velocity be” —> we are looking for a velocity in the future. This is the final velocity vf = ?

Knowns: vi, a, t

Unknown: vf

We need an equation with vi, a, t, and vf in it

Equations to choose from:

Vf= Vi + a*t

Vf^2 = Vi^2 + 2*a *x

x = Vi*t + 1/2*a*t^2

With our knowns and unknowns, we will choose equation 1 and plug in our values for vi, a, and t to find vf:

vf = vi + a * t

vf = 0 + (4.6)*(12.3)

vf = 0 + 56.58

vf = 56.58 m/s