# A runner covers the last straight stretch of a race in 4 s. During that time, he speeds up from 5 m/s to 9 m/s. What is the runner

A runner covers the last straight stretch of a race in 4 s. During that time, he speeds up from 5 m/s to 9 m/s. What is the runner’s acceleration in this part of the race?

### 1 thought on “A runner covers the last straight stretch of a race in 4 s. During that time, he speeds up from 5 m/s to 9 m/s. What is the runner”

1. niczorrrr
Given,
Time taken to cover the last last straight stretch of a race = 4 seconds
He speeds up from 5 m/s to 9 m/s
To find,
The acceleration of the runner.
Solution,
We can simply solve this numerical problem by using the following process.
Here,
Initial velocity (u) = 5 m/s
Final velocity (v) = 9 m/s
Time (t) = 4 seconds
Acceleration (a) = ?
According to the formula of kinematics,
a = (v-u)/t
a = (9-5)/4 [By putting the given values.]
a = 4/4 = 1 m/s²
(We have used SI unit of the acceleration, because all the initial physical quantities are also in SI units.)
Hence, the acceleration is 1 m/s²