Question

A sprinter speeds up to 3 m/s during the last 2 seconds of the race with an

acceleration of 0. 4 m/s 2 . What was the initial speed of the sprinter?

Answer 1

The initial speed of the sprinter was 2.2 m/s

Step-by-step explanation:

Constant Acceleration Motion

It's a type of motion in which the velocity of an object changes by an equal amount in every equal period of time.

The following relation applies:

`v_f=v_o+at`

Where a is the constant acceleration, vo the initial speed, vf the final speed, and t the time.

The sprinter speeds up from an unknown initial speed to vf=3 m/s in t=2 seconds with an acceleration of
`a=0.4~m/s^2`.

To find the initial speed, we solve the equation for vo:

`v_o=v_f-at`

Substituting the values:

`v_o=3-0.4*2`

`v_o=3-0.8`

`v_o=2.2~m/s`

The initial speed of the sprinter was 2.2 m/s