Question 10 (5 pts.):​ Why do you think cholera would choose to colonize the intestines of its host, as opposed to other parts of the body? (Try to think about what the bacteria might gain from living in the intestines.)

Question 11 (5 pts.):​ Why do you think it is important for ​V. cholerae​ to attach themselves firmly to the epithelial cells of the intestines, as shown in the picture above?

Question 12 (5 pts.):​ Suggest a reason why ​V. cholerae​ would benefit by causing their hosts to have excessive, watery diarrhea? How could this help the bacteria in their cycle of infection?

Consider the following special cases of collisions. In all cases, a cart of m1m1 comes in with a velocity vv and hits a cart m2m2coming in with velocity −v−v (same speed vv from the opposite direction). Most of these are answerable with either intuition or with mathematics. What are the final velocities of both carts if:

a. The collision is elastic, and both carts are the same mass? (Two swords collide in a swordfight)

b. The collision is inelastic, and both carts are the same mass? (Two identical twins charge-tackle each other)

c. The collision is elastic, and the mass of the first cart is much larger than the mass of the second cart? (Sword hits a dagger in a swordfight)

A professor tests whether the loudness of noise during an exam (low, medium, and high) is independent of exam grades (pass, fail). The following table shows the observed frequencies for this test.

Noise Level

Low Medium High

Exam Pass 20 18 8 46

Fail 8 6 10 24

28 24 18 N=70

(a) Conduct a chi-square test for independence at a 0.05 level of significance. (Round your answer to two decimal places.)

x^2{obt}=

(b) Compute effect size using Cramer's V. (Round your answer to two decimal places.)

V =

Ken has a coin that has probability 1/5 of landing Heads.

   Mary has a coin that has probability 1/3 of landing Heads.

   They toss their coins simultaneously, repeatedly.

Let X be the number of tosses until Ken gets his first Heads.

Let Y be the number of tosses until Mary gets her first Heads. Find:

Let U = min(X,Y) and V = max(X,Y)

(d) For k = 1, 2, 3,... , find a formula for P(U = k).

(e) For k = 1, 2, 3,... , find a formula for P(V > k). HINT: Inclusion-Exclusion.

The spin cycles of a washing machine have two angular speeds, 416 rev/min and 632 rev/min . The internal diameter of the drum is 0.560 m

Part A

What is the ratio of the maximum radial force on the laundry for the higher angular speed to that for the lower speed? (F higher/F lower)=?

Part B

What is the ratio of the maximum tangential speed of the laundry for the higher angular speed to that for the lower speed? (V higher/ V lower)=?

Part C

Find the laundry's maximum tangential speed . (m/s)

Part D

Find the laundry's maximum radial acceleration, in terms of g . (a rad=? g)

63. Human ageing is a rapidly evolving area of health research because (select all that apply):

1. Nutrition and its potential impacts on lifelong health is better understood today.
2. Genes can be easily modified in humans to prolong life.
3. Epigenetics is increasingly important in predicting lifelong health.
4. We can better predict the risks of disease via genetic studies.
5. All people are now more likely to understand and apply information about healthy choices.

Select one:

A. I, IV, V

B. I, II, III, IV, V

C. II, III, IV

D. I, III, IV

In the “old days”, televisions were made from Cathode Ray Tubes whereby a beam of
electrons rapidly swept across the inside of the screen as a result of strategic deflections
from magnetic fields acting on the beam. Suppose that Frank has a massive 2000 inch
TV in which the image has to be updated 100 times per second (to minimize the
appearance of “flicker”) and that there are 100,000 rows.
(a) Show that the electron beam moves across the screen with a speed v  c .
(b) Explain why this superluminal speed does not contradict relativity. In particular, why
can’t information be transmitted from one side of the screen to the other with v  c ?

For the sentences in (1):

1. Identify each V:

   o Give its subcategorization frame (based on the sentence it appears in).

2. o List the thematic roles it assigns.

For example:

Ex. John hit Bill in the mouth
hit - V [ ___ NP ] (Agent, Theme)
[NP John ] – Agent, [NP Bill ] – Theme, [NP the mouth ] – Goal

(Theta-roles are discussed in the textbook in the semantics chapter, on pages 158-161.)

(1)

a. The torpedo sank the boat
b. The captain sank the boat with a torpedo
c. A brick fell from the sky onto Fred’s big toe
d. Bill heard that John joined the army from Mary