Question

At the starting gun, a runner accelerates from rest at 2.0 m/s² for 2.2 s. What is the runner’s speed 1.2 s after she starts running? (Express answer to two sig figs)

A) 3.2 m/s
B) 4.0 m/s
C) 4.4 m/s
D) 5.6 m/s

Answer 1

The runner's speed after 1.2 seconds of acceleration from rest at 2.0 m/s² is calculated to be 2.4 m/s using the formula V = u + at. However, this answer does not match any of the provided options, suggesting there might be a discrepancy in the question or the given choices.

Step-by-step explanation:

To calculate the runner's speed 1.2 seconds after she starts running, we can use the equation for constant acceleration, which is V = u + at, where V is the final velocity, u is the initial velocity (which is zero since the runner starts from rest), a is the acceleration, and t is the time.

Given that the acceleration a is 2.0 m/s² and the time t is 1.2 s, we substitute these values into the equation:

V = 0 + (2.0 m/s²)(1.2 s)

V = 2.4 m/s

The runner's speed after 1.2 seconds of acceleration is therefore 2.4 m/s. However, this is not one of the provided options (A, B, C, D). It seems there is likely to have been a miscalculation in the question, the wrong options have been provided, or the question might be missing some additional information.