Answer:
Runner will run for 210m
Step by Step Explanation:
According to Newton's first of motion,
Vf=Vi+at
Given is
the speed with which runner is running will be Vi, he is running with accelertion a=4.2m/s2 fot time t=10sec
Vf will be 0 because runner will stop after winning the race
we will find Vi from equation 1,
Vi=Vf-at
= 0- 4.2*10
=-42 m/s (negative sign is showing decceleration)
So, Vi=42 m/s
According to Newton's third of motion,
2aS= Vf^2-Vi^2
S is distance, he will cover before stopping,
2(4.2)S= 0- 42^2
S=1764/8.4
S=210m
Runner will run for 210m
