Question

A car initially at rest accelerates for 4 seconds to reach a final velocity of 20 m/s. Determine the acceleration of the car.

A) 5 m/s^2
B) 10 m/s^2
C) 4 m/s^2
D) 2.5 m/s^2

Answer 1

The acceleration of a car accelerating from rest to a velocity of 20 m/s in 4 seconds is calculated as 5 m/s² using the formula a = ∆v / ∆t.

Step-by-step explanation:

The student is asking about the acceleration of a car that starts from rest and reaches a specific velocity after a given time. The acceleration can be found using the formula a = ∆v / ∆t, where a is the acceleration, ∆v is the change in velocity, and ∆t is the time taken for this change. The change in velocity (∆v) is the final velocity minus the initial velocity. As the car is starting from rest, its initial velocity is 0 m/s. Therefore, ∆v is simply the final velocity of the car.

In the given problem, the car accelerates from rest (initial velocity = 0 m/s) to a final velocity of 20 m/s in 4 seconds. Thus, ∆v = 20 m/s, and ∆t = 4 s. Using the formula :

a = ∆v / ∆t = 20 m/s / 4 s = 5 m/s²

Hence, the acceleration of the car is 5 m/s², which corresponds to option A).