Question

A car accelerates at 2 m/s^2. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20m/s?

A. 2 sec
B. 10 sec
C. 20 sec
D. 40 sec

Answer 1

Using the kinematic equation v = u + at, where v is the final velocity, u is the initial velocity, a is the acceleration, and t is the time, the car needs 10 seconds to accelerate to a speed of 20 m/s from rest.

Step-by-step explanation:

To solve this physics problem involving acceleration and time, we can use the kinematic equation: v = u + at, where:

• v is the final velocity (20 m/s),
• u is the initial velocity (0 m/s, since the car starts from rest),
• a is the acceleration (2 m/s2), and
• t is the time, which we are solving for.

Rearranging the equation to solve for time, t, we get: t = (v - u) / a.

Plugging in the values we get: t = (20 m/s - 0 m/s) / 2 m/s2 = 10 seconds.

Therefore, the car needs 10 seconds to accelerate to a speed of 20 m/s from rest. The correct option is B. 10 sec.