HW. Physical Science

Stopping Distance and Kinetic Energy
Chapter 6

You have until Tuesday Nov. 26 to turn this assigment.
Is not in your not book, this is to be done in a seperate sheet of paper with your name.
Individual work.

Chapter 6

Stopping distance and Kinematic Energy

Instructions:

Solve the following problems according to the instruction of each. Show your work in the space provide below each question. Round your answers to two decimals after the period.

Assumptions:

The car is traveling is straight line.

All conditions are normal or optional

The car slows at a constant acceleration of -5.0m/s2, when the breaks are applied under the above conditions.

Suppose a car is moving 11.2m/s. How far will it take the car to stop if it decelerates at -5.0m/s²?

1.       The car slows from 11.2 m/s to 0.0m/s; therefore, the average velocity will be:

2.       To find the distance, you must find the time interval, having that acceleration is equal to the division between the velocity interval and the time interval, clear the formula for time interval.

3.       Determinate the distance, using d=v_avg x Time interval

4.       Complete the table for these additional velocities

22.3m/s

33.5m/s

Velocity	Time (s)	Distance (m)
11.2m/s
22.3m/s
33.5m/s

5.       Suppose that the car in the previous problem has a mass of 2200Lbs. How much kinetic energy will it have a speed of 11.2m/s? (KE=1/2mv²)

6.       Complete the table

Velocity	Kinetic Energy (J)
11.2m/s
22.3m/s
33.5m/s

7.       Discussion questions:

a.       Give two important driving principles illustrated by this study.

b.      Which of the assumptions is the most unrealistic? Why?

c.       List some factors discussed in the facet on page 144 of your textbook that make one or more of these assumptions invalid in the real world.