Posted by **jane john** on Thursday, June 10, 2010 at 10:48am.

A runner hopes to complete a 10,000 m race in a time of 30

minutes. After running at a constant speed for exactly 27 minutes,

there are still 1100 m to go. The runner then accelerates at

0.2 m/s2 for how many seconds in order to achieve the desired

time?

- physics -
**drwls**, Thursday, June 10, 2010 at 2:27pm
The runner wants to go the remaining 1100 m in 3 minutes. That will require an average speed of 6.11 m/s. His speed for the first 2700 minutes was

8900m/(27*60 s) = 5.49 m/s.

If he accelerates for time T (seconds) and then maintains constant speed for 180-T seconds,

Final speed Vf = 5.49 + 0.2 T

Distance travelled in final 3 minutes

1100 = Vf*(180-T) + (Vf + 5.49)T/2

Substitute 5.49 +0.2T for Vf in the final equation and solve for T.

- physics -
**Anonymous**, Thursday, September 4, 2014 at 3:04pm
12.4

## Answer this Question

## Related Questions

- physics - A runner hopes to complete the 10,000m run in less than 30 minutes. ...
- Physics Problem - A runner hopes to complete the 10,000m run in less than 30 ...
- Physics (Algebra Bit) - I still need help on my other question as well... A ...
- Maths - Three runners run a 10 metre race. Each runner runs according to the ...
- Physics - An athlete wants to complete the 4000 m run in 12.0 minutes. After ...
- Physics - During a rElay race along a straight ROAD the 1st runner on a three ...
- statistics - Let x denote the time taken to run a road race. Suppose x is ...
- Physics - Runner A is running at a constant rate of 2.3 m/s when he passes ...
- physics - Runner A is running at a constant rate of 2.3 m/s when he passes ...
- Maths - A runner runs a 10 metre race, the runner runs according to the ...

More Related Questions