A motorcyclist sees a branch in the road, and hits the brakes, slowing down at -6.42 m/s^2. If it takes him 2.85 s to stop, what was his starting velocity?

his starting velocity was 18.297 ms⁻¹

Explanation:

v = u + at (1)

Where

Final Velocity (v) = 0 ms⁻¹

Initial velocity (u) = ?

Acceleration (deceleration) (a) = -6.42 ms⁻²

time (t) = 2.85 s

Substituting all parameters into equation (1)

0 = u + (-6.42)2.85

0 = u + (-18.297)

0 = u - 18.297

18.297 = u

∴ the initial velocity was 18.297 ms⁻¹

answer: the correct answer for the fill in the blank is rods.

rods are the specialized photoreceptor cells that are present in the retina of human eye. they are responsible for vision in the night time ( also called scotopic vision). they have very low visual acuity and color distinguishing ability.

as they are responsible for vision in night time, therefore they are found predominantly in the nocturnal animals.