# Athletic competition

In a 400 meter athletic competition, a participant covers the distance as given below.
find the average speed?

first 80 meters 10 m/s
next 240 meters 7.5 m/s
last 80 meters 10 m/s

Correct result:

v =  8.333 m/s

#### Solution:

$s=vt \ \\ s_{1}=80 \ \text{m} \ \\ s_{2}=240 \ \text{m} \ \\ s_{3}=80 \ \text{m} \ \\ \ \\ v_{1}=10 \ \text{m/s} \ \\ v_{2}=7.5 \ \text{m/s} \ \\ v_{3}=10 \ \text{m/s} \ \\ \ \\ t_{1}=s_{1}/v_{1}=80/10=8 \ \text{s} \ \\ t_{2}=s_{2}/v_{2}=240/7.5=32 \ \text{s} \ \\ t_{3}=s_{3}/v_{3}=80/10=8 \ \text{s} \ \\ \ \\ v=\dfrac{ s_{1}+s_{2}+s_{3} }{ t_{1}+t_{2}+t_{3} }=\dfrac{ 80+240+80 }{ 8+32+8 }=\dfrac{ 25 }{ 3 }=8.333 \ \text{m/s}$

Our examples were largely sent or created by pupils and students themselves. Therefore, we would be pleased if you could send us any errors you found, spelling mistakes, or rephasing the example. Thank you!

Please write to us with your comment on the math problem or ask something. Thank you for helping each other - students, teachers, parents, and problem authors.

Tips to related online calculators
Looking for calculator of harmonic mean?
Looking for a statistical calculator?
Do you want to convert length units?
Do you want to convert velocity (speed) units?
Do you want to convert time units like minutes to seconds?

## Next similar math problems:

• Car overtaking
A passenger car travels at a speed of 30 m/s, and before it travels freight truck that drives at a constant speed of 10 m/s. Within 30 meters of the truck, the driver of the car finds out that the truck can not overtake. That's why it starts braking with
• Bob traveled
Bob traveled 20 meters to Dave's house. He arrived in 3 minutes. What was his average speed for the trip.
• Freight and passenger car
The truck starts at 8 pm at 30 km/h. Passenger car starts at 8 pm at 40 km/h. Passenger arrives in the destination city 1 hour and 45 min earlier. What is the distance between the city of departure and destination city?
• Bomber
The aircraft flies at an altitude of 4100 m above the ground at speed 777 km/h. At what horizontal distance from the point B should be release any body from the aircraft body to fall into point B? (g = 9.81 m/s2)
• Distance between two cities
Car went from A to B 4h. On the way back, the car was up 15km / h faster. The return trip took 48 minutes. Shorter than the way there. Find the distance of the cities A and B.
• Cars 2
Opava is 360 km distance from Prešov. At 8:00 hour two cars started against each other from this cities at average speeds 88 km/h and 121 km/h. At what hour its will meet and what distance its travel if car started from Prešov is faster?
• Cyclist vs car
Cyclist rode out of the city at 18 km/h. 1 hour 30 minutes behind him started car and caught up with the cyclist in 50 minutes. How fast was driving the car? Where (what kilometer) from the city car overtook a cyclist?
• Wavelength
Calculate the wavelength of the tone frequency 11 kHz if the sound travels at speeds of 343 m/s.
• The cyclist
The cyclist drove from A to B, 60 km away. The first half drove at 30km/h, the second at 20km/h. How long did it take for him?
• The tourist
The tourist traveled 78km in 3 hours. Part of the journey went on foot at 6km/h, the rest of the trip by bus at 30km/h. How long did he walk?
• Two vans
At 8:30 a. M. , two vans leave at a parking area. They travel in opposite directions: one van travels at 48 km/h and the other at 62 km/h. At what time will the cars be 550 km apart?
• Constant motion
The car has undergone constant motion 120 km in 1 hour 30 minutes. Determine its average speed. Determine how long car drove in the first 20 minutes and 50 minutes from the start of the move.
• Cyclist and car
A cyclist who runs at a speed of 20km per hour will arrive at the finish in 4.5 hours. How fast does the car have to drive the same route in 2 hours?
• Cyclist 9
A cyclist travels at a a speed of 4.25 km per hour. At that rate, how far can he travel in 3.75 hours?
• Free fall
The free fall body has gone 10m in the last 0.5s. Find the body speed at the moment of impact.
• Walkers
From points A and B simultaneously started against each other two walkers. After meeting both continue to B. Second walker came to B 2 hours before the first walker. It's speed is 2.7 times of speed of the first pedestrian. How many hours went pedestrians
• Wave parameters
Calculate the speed of a wave if the frequency is 336 Hz and the wavelength is 10 m.