When the race started, juan’s speed increased until he was running at a constant speed of 6 m/s. after 17 seconds, juan’s velocity changed to 5 m/s to the northwest and remained constant for 20 seconds. finally, juan’s velocity changed to 7m/s north, and he crossed the finish line. juan then walked back to the starting line at a slow constant speed of 1 m/s.

6.what are examples of speed from the description of juan's race?

7.what are examples of velocity from the description of juan's race?

8.what are examples of acceleration from the description of juan's race?
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1)

when Juan is running at constant speed of 6 m/s and when Juan walked back to starting line at constant speed of 1 m/s

2)

Juan velocity changed to 5 m/s to North West

Juan velocity changed to 7 m/s North

3)

Juan velocity changed to 5 m/s to North West

Juan velocity changed to 7 m/s North

Explanation:

Part a)

As we know that speed is rate of change in the position

so if the position is changing with time without considering the direction then it is known as speed

so correct description for speed is

when Juan is running at constant speed of 6 m/s and when Juan walked back to starting line at constant speed of 1 m/s

Part b)

When rate of change in position is described along with the direction then it is known as velocity

so the correct description for velocity is given as

Juan velocity changed to 5 m/s to North West

Juan velocity changed to 7 m/s North

Part c)

Rate of change in velocity is known as acceleration so we need to know change in velocity and time interval to find the acceleration

so here acceleration is described as

Juan velocity changed to 5 m/s to North West

Juan velocity changed to 7 m/s North

it doesn't. it was imagined up in the middle ages.

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