Find the Optimal Starting Time for a Tied Race in Physics Kinematics

In summary, John runs at a speed of 5 m/s while Joe runs at a speed of 3 m/s. The distance they have to run is 300 m. In order to make the race more exciting, Antony allows John to start t seconds after Joe. The t value needed for the race to finish in a tie is 40 seconds, and the distance allowed to Joe is 120 m.
  • #1
leprofece
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John runs at 5 m/s joe runs at 3m/seg the distance to run is 300 m Antony in order to do the race more exciting allows john start t seconds after joe What is the t value so that the race finishes in a tie?? what distance was allowed to joe?? Answer 40 seg and 120 m

I don't know how to denote the time of john
5t = 3 (300-t) ?'
 
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  • #2
Let's let $T$ represent the time John runs, and so $T+t$ is the time Joe runs. We know the must both run 300 m during their respective times, and so we may write:

\(\displaystyle 5T=3(T+t)\)

\(\displaystyle 5T=300\implies T=60\)

Can you proceed?
 
  • #3
sure 5T -3T = t
2 T = t
t = 2 *60 = 120
please I am not Sure cooecte me if I am not correct
and thanks for you reply greetings and regards
 
  • #4
You should have:

\(\displaystyle 5T-3T=3t\)

You didn't distribute the $3$ before...:D
 
  • #5
2T = 3t

2(60) = 3t
so t = 40 seg

Ok and now: 3 (40) = 120 m

ithink i am ruight now do I?
 
  • #6
leprofece said:
2T = 3t

2(60) = 3t
so t = 40 seg

Ok and now: 3 (40) = 120 m

ithink i am ruight now do I?

Yes, that's correct! (Sun)
 

FAQ: Find the Optimal Starting Time for a Tied Race in Physics Kinematics

What is kinematics?

Kinematics is the study of motion, specifically the position, velocity, and acceleration of an object without considering the causes of the motion.

What is the difference between speed and velocity?

Speed is a scalar quantity that measures the rate of motion, while velocity is a vector quantity that measures the rate of motion and the direction of that motion.

What is the difference between average and instantaneous velocity?

Average velocity is the total displacement divided by the total time, while instantaneous velocity is the velocity at a specific moment in time.

What is the difference between average and instantaneous acceleration?

Average acceleration is the change in velocity divided by the change in time, while instantaneous acceleration is the acceleration at a specific moment in time.

What is the difference between distance and displacement?

Distance is a scalar quantity that measures the total path traveled, while displacement is a vector quantity that measures the change in position from the starting point to the ending point.

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