Joseph deloach of the united states set an olympic record in 1988 for the 200-meter dash with a time of 19.75 seconds. what was his average speed? give your answer in meters per second and miles per hour.

The average speed was 10.12 m/s or 22.96 mi/h

Explanation:

The average speed is defined as:

  (1)

Where d is the total distance traveled and t is the passed time.

For the special case of Joseph DeLoach, he traveled a total distance of 200 meters in 19.75 seconds. Those values can be introduced in equation 1:

That means that Joseph DeLoach traveled a distance of 10.12 meters per second.

To represent the result in miles per hour, it is necessary to know that 1 mile is equivalent to 1609 meters.

⇒ 0.124 mi

it is needed to express the given time in units of hour. 1 hour is equivalent to 3600 seconds.

⇒ 0.0054 h

Then, equation 1 is used with the new representation of the values.

the closer the planet is to the sun, the larger the gravity

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s