Question

help please!! A runner at a speed of 3.5 m/s comes to a stop in 0.15 seconds. What is the deceleration?

Answer 1

Answer:

Deceleration of the runner is -23.33 $\frac{m}{s^{2} }$

Given:

Initial velocity = 3.5 $\frac{m}{s}$

Final velocity = 0 $\frac{m}{s}$

Time = 0.15 s

To find:

Deceleration of runner = ?

Formula used:

According to first equation of motion,

v = u + at

Where, v = final velocity

u = initial velocity

a = deceleration

t = time

Solution:

According to first equation of motion,

v = u + at

Where, v = final velocity

u = initial velocity

a = deceleration

t = time

0 = 3.5 + a (0.15)

-3.5 = 0.15 (a)

a = $\frac{-3.5}{0.15}$

a = -23.33 $\frac{m}{s^{2} }$

Negative sign shows that it is deceleration.

Thus, deceleration of the runner is -23.33 $\frac{m}{s^{2} }$