Question

A person starts to run at 12 m/s and then comes to a rest in

3s.
What is their velocity at 1 second

Answer 1

Velocity at 1 second = 8 m/s

Further explanation

Linear motion consists of 2: constant velocity motion with constant velocity and uniformly accelerated motion with constant acceleration

• An equation of uniformly accelerated motion

V = vo + at

Vt² = vo² + 2a (x-xo)

x = distance on t

vo / vi = initial speed

vt / vf = speed on t / final speed

a = acceleration

• acceleration

A person starts to run at 12 m/s and then comes to rest in 3s.

At rest vf=0

vi=12 m/s

t = 3 s

`\tt vf=vi-at(a=-, deceleration)\\\\0=12-a.3\\\\12=a.3\Rightarrow a=4~m/s^2`

• velocity at 1 second

`\tt vf=12-4.1\\\\vf=8~m/s`