At the starting gun a runner accelerates from rest at 1.9 m/s2 for 2.2s. what is the runner’s speed 2s after she starts running?

= 3.8 m/s

Explanation:

When the runner start the running, she is at rest. So the initial velocity of the runner is zero (0 m/s). And then she accelerates at  a rate of 1.9 m/s² for 2.2 s. But we need to find the final velocity after t = 2 s when she starts the running. So, we take time equal to 2 second.

Given data:

Initial velocity = = 0 m/s

Acceleration = a = 1.9 m/s²   (for 2.2 s after starting the race)

Time = t = 2 s

Final velocity = = ?

According to the First equation of motion

=   + at

= 0 + (1.9)(2)

= 3.8 m/s

i think it’s a. this is because if they measured the mass of something with a mass of 150g, then their final answer would have to be approximately 150g. though all of their answers are almost 150, rosa and tran have the closest answers (or the exact answer) to the accurate one.

the right answer is 0.3 meters per second