11)A race car travels on a racetrack at 38 m/s and slows at a constant rate to a velocity of 20 m/s over 10 s. How far does it move during this time?

I don't know

12)The speed of a body is the distance traveled per unit time. Which of the following would be SI units of speed?

A)meters per second
B)miles per hr
C)kg per hr
D)both A and B

I got D

12:

Only A is SI units of speed. B is speed, but it is English units, NOT SI.
The correct answer should be A.

11) To find the distance the race car moves during this time, we can use the formula:

distance = average velocity x time

Since the car is slowing down at a constant rate, we can find the average velocity by taking the average of the initial velocity (38 m/s) and the final velocity (20 m/s):

average velocity = (initial velocity + final velocity) / 2

average velocity = (38 m/s + 20 m/s) / 2

average velocity = 58 m/s / 2

average velocity = 29 m/s

Now we can use the average velocity and the time (10 s) to find the distance:

distance = average velocity x time

distance = 29 m/s x 10 s

distance = 290 meters

Therefore, the race car moves a distance of 290 meters during this time.

12) You are correct, the SI units of speed are meters per second (m/s). This is option A. Additionally, miles per hour (miles/hr) is also a unit of speed, so option B is correct. Therefore, the correct answer is D, both A and B.