When running a 100 meter race Jamal reaches

Question

When running a 100 meter race Jamal reaches his maximum speed when he is 35 meters from the starting line, and 7 seconds have elapsed since the start of the race. Jamal continues at this max speed for the rest of the race and is 67 meters from the starting line 11 seconds after the start of the race.

What is Jamal's max speed?

Suppose Jamal runs for an additional 2 seconds after reaching his max speed...

How far will Jamal travel during those 2 seconds?

What is Jamal's distance from the starting line 9 seconds after the start of the race?

What is Jamal's distance from the starting line 8.5 seconds after the start of the race?

Answer 1

1) He run from 35th m to 67th m and from 7th sec to 11th sec with max speed, so his max speed is,

V_max = (67 - 35) / (11 - 7) = 8 m/s

2)if he runs 2 sec more with max speed,

Distance₁ = 2 s * 8 m/s = 16 m

3) at 7th sec, where he started to run at max speed, he is 35 m from the starting line speed. so 9th sec is 2 sec later from that instant, and we already calculated how far he runs in 2 sec at max speed at (2) which is 16 m. So,

Distance₂ = 35 m + 16 m = 51 m

4) At 8.5 sec means first 7 sec (35m) plus 1.5 sec at max speed. So,

Distance₃ = 35 m + 8 m/s * 1.5 s = 35 + 12 = 47 m