Answer:
vf= 4.4 m/s
Explanation:
Kinematics
Because the sprinter moves with uniformly accelerated movement we apply the following formula:
vf= v₀+at Formula (1)
Where:
t : time in seconds (s)
v₀: initial speed in m/s
vf: final speed in m/s
a: acceleration in m/s²
Data
t = 4 s
v₀ = 10 m/s
a = -1.4 m/s²
Problem development
We replace data in the formula (1) to calculate the speed of the sprinter in 4 seconds :
vf = 10-1.4(4)
vf= 4.4 m/s
