Starting from rest, a car travels 18 meters per second as it accelerates uniformly for 3.0 seconds. What is the magnitude of the car’s acceleration? *

Question

A-18 meters per second

B-6 meters per second

C- 13 meters per second square

D-6 meters per second square

Answer 1

Given:

Velocity Initial = Vo = 0

Velocity = V = 18 m/s

Time = 3.0 seconds

Find:

Acceleration = a

Solution:

Uniform acceleration implies that the acceleration is constant

Therefore, we can utilize our kinematic equations.

A car starts at rest, then goes to a velocity of 18 m/s. We want to see the acceleration that

it experiences as it picks up in speed in a specific time interval. t = 3 seconds

Now, we have various kinematic equations we can utilize.

Based on the variables provided we use the kinematic equation that is derived when acceleration

is a function of time. a = f(t)

Note: a = dv/dt

adt = dv

This derivation yields:

at + Vo = V

Now, for your introductory physics class you do not need to know this much detail.

But it is always resourceful to understand where you get these equations from.

That way you rely on your conceptual understanding of the topic, rather then a formula sheet.

To continue with this problem

V = at + Vo

Set Vo = 0

V = at

Solve for a

a = V/t = 18/3 = 6 meters/ second ^2

Your answer is option B