You have been hired as an expert witness in a court case involving an automobile accident. The accident involved a car of mass 1870 kg (car A) which approached a stationary car of mass 1020 kg (car B). The driver of car A applied his brakes 10 m before he crashed into car B. After the collision, car A slid 17 m while car B slid 30 m. The coefficient of kinetic friction between the locked wheels and the road was measured to be 0.60. Reconstruct the accident by calculating all the relevant velocities.

a.The speed of car A just before the breaks were applied.

b.The speed of car A just before the collision.

c. The speed of car A just after the collision.

d.The speed of car B just after the collision.

4. A market research company wants to assess the potential for purchasing a new product "before" and "after" an individual sees a television advertisement about that product. The ranking of potential purchases is based on a scale of 0 to 10, with a higher value indicating a higher purchase potential. The null hypothesis states that the average rating of "After" will be less than or equal to the average value of "before." A rejection of this hypothesis will show that advertising increases the average potential buying rank. Use α = 0.05 and the following data to test the hypothesis.

Given: 2 balls collide

m1= 0.126 kg          m2=0.126 kg

Before collision:

Yx(initial)= 4.00 m/s         V2x(initial)= -2.00 m/s

Yy(initial)= 1.50 m/s          V2y(initial)= 2.00 m/s

After collision:

V1x(final)= -0.482 m/s            V2x(final)= 2.482 m/s

V1y(final)= 2.020 m/s             V2y(final)= 1.480 m/s

Calculate the x and y components of the total momentum of the system before the collision.

Calculate the x and y components of the total momentum of the system after the collision.

Is the momentum conserved? Explain.

Calculate the total momentum of the system before the collision.

Calculate the total momentum of the system after the collision.

Is the collision elastic, partially elastic, or inelastic?

A fitness company conducted an experiment on multiple volunteers for their 15-day “beach body” weight loss program. Their before and after weights were taken and the results are listed in the Homework 3.xlsx file on the sheet named “Problem 5”.   

a. What is the average before weight of the group?

b. What is the average after weight of the group?

c. Using an appropriate confidence interval, determine if the program was effective over the 15-days in helping people lose weight.

A school psychologist wishes to determine whether a new anti-smoking film actually reduces the daily consumption of cigarettes by teenage smokers. The mean daily cigarette consumption is calculated for each of eight teenage smokers during the month before and the month after the film presentation, with the following results: MEAN DAILY CIGARETTE CONSUMPTION

SMOKER NUMBER BEFORE FILM (X1) AFTER FILM (X2)

1 28 26

2 29 27

3 31 32

4 44    44

5 35 35

6 20 16

7 50 47

8 25 23

A) Is there a significant difference in the number of cigarettes smoked before the film as compared to the number of cigarettes smoked after the film?

B) What does this NOT necessarily mean?

C) What might be done to improve the design of this experiment?

A school psychologist wishes to determine whether a new anti-smoking film actually reduces the daily consumption of cigarettes by teenage smokers. The mean daily cigarette consumption is calculated for each of eight teenage smokers during the month before and the month after the film presentation, with the following results: MEAN DAILY CIGARETTE CONSUMPTION

SMOKER NUMBER BEFORE FILM (X1) AFTER FILM (X2)

1 28 26

2 29 27

3 31 32

4 44 44

5 35 35

6 20 16

7 50 47

8 25 23

A) Is there a significant difference in the number of cigarettes smoked before the film as compared to the number of cigarettes smoked after the film?

B) What does this NOT necessarily mean?

C) What might be done to improve the design of this experiment?

The U.S. supply and demand curves for cars cross at $10,000. Foreigners will purchase any quantity of American cars for $15,000 each. One day, the government imposes a tax of $2000 export tax on every American car sold to a foreigner. (Cars sold to Americans are not taxed.) What price must Americans pay for a car before the tax is imposed? What price must Americans pay for a car after the tax is imposed? What price do American producers feel they are receiving for a car before the tax is imposed? What price do American producers feel they are receiving for a car after the tax is imposed? Before and after the tax is imposed, show in a diagram the gains and losses to all relevant groups of Americans. What is the deadweight loss due to the tax?

A pilot study is run to investigate the effect of a lifestyle intervention designed to increase medication adherence in patients with HIV. Medication adherence is measured as the percentage of prescribed pills that are taken over a one-week observation period. Ten patients with HIV agree to participate and their medication adherence before and after the intervention are shown below. Compute the standard deviation of the difference in adherence before versus after intervention. Please show your work and explain.Thank you!

While feverishly studying for this test, you suddenly realized that it had been over 12 hours since you last ate. You then took a break, drove over to Waffle House (restuarant), and ate a huge breakfast. Please describe the following IN ORDER:

a) your blood glucose and hormonal status, both before and after your meal;

b) what metabolic processes were up-regulated before and after your meal;

c) what metabolic processes were down-regulated before and after you meal;

d) what specific enzymes were affected and in what direction in (b) and (c) above;

e) why your answers to (b) and (c) above make sense for you as a complex, multicellular, energy-conscious organism.

Calculate: What is the population change/growth, natural increase, and net migration for each of the four populations. Fill in the table below. Hint: estimate using the “Demographic Balancing Equation.” Hint: In the table, you can express answers absolute numbers.

Calculate: Using data from the above table/calculations, what is the net-migration rate for Oakwood during this ten-year period (2000-2010)? Hint: assume that all migration and natural increase was evenly spaced during the ten-year interval between 2000 and 2010. This assumption should help you figure out an estimate of the mid-year population for Oakwood.    

                                                                                                     ____________________ (per 1000)

Discuss: Using the above data/calculations, can you estimate the gross migration rate of these four populations? Why or Why not?