Question

A car accelerates uniformly from rest to a speed of 20 m/s in 10 seconds. What is the car's acceleration?

• A. \( 2.0 \, \text{m/s}^2 \)
• B. \( 1.0 \, \text{m/s}^2 \)
• C. \( 0.5 \, \text{m/s}^2 \)
• D. \( 4.0 \, \text{m/s}^2 \)

Hint:

Acceleration can be calculated from the change in velocity over time. If the object is at rest initially, the formula simplifies to \( a = \frac{v}{t} \).

Answer 1

The Correct Option is A

To determine the car's acceleration, we will use the formula for uniform acceleration:

\[ a = \frac{v - u}{t} \]

Where:

• \( v \) = final velocity = \( 20 \, \text{m/s} \)
• \( u \) = initial velocity = \( 0 \, \text{m/s} \) (since the car starts from rest)
• \( t \) = time = \( 10 \, \text{s} \)

Substituting the values:

\[ a = \frac{20 \, \text{m/s} - 0 \, \text{m/s}}{10 \, \text{s}} = \frac{20 \, \text{m/s}}{10 \, \text{s}} = 2.0 \, \text{m/s}^2 \]

Therefore, the car's acceleration is \( 2.0 \, \text{m/s}^2 \). However, based on the provided options, none of the given choices matches our calculated answer.