Harry's Hardware purchases the items shown from the wholesalers. Find the trade discount and net price for each item.

Item	List	Trade-Discount Rate
Paint thinner	$12.95	35%
Lawn fertilizer	8.99	10%
B&D electric saw	58.95	15%

An electron and a proton are each moving at $735 \mathrm{~km} / \mathrm{s}$ in perpendicular paths as shown in Fig. we saw earlier. At the instant when they are at the positions shown, find the magnitude and direction of the total electric force and the total magnetic force that the electron exerts on the proton.

An unusually wet spring has caused the size of the Cape Cod mosquito population to increase by $8 \%$ each day. If an estimated 200,000 mosquitoes are on Cape Cod on May 12, find how many mosquitoes will inhabit the Cape on May 25 . Use $y=200,000(1.08)^{\dot{x}}$ where $x$ is the number of days since May 12. Round to the nearest thousand.

Wet your finger and rub it slowly around the rim of a thinrimmed, stemmed wine glass while you hold the base of the glass firmly to a tabletop with your other hand. The friction of your finger will excite standing waves in the glass, much like the wave made on the strings of a violin by the friction from a violin bow. Try it with a metal bowl and explain.

Two point charges $Q$ and $+q$ (where $q$ is positive) produce the net electric field shown at point $P$ in Fig. we saw earlier . The field points parallel to the line connecting the two charges.(a) What can you conclude about the sign and magnitude of $Q$ ? Explain your reasoning.

Some accountants show losses by enclosing the number in parentheses. For example, a loss of $\$ 1500$ could be shown by ( $\$ 1500)$. a. How would the accountant record the amounts in Learning Exercise we saw earlier? b. How would the account record a gain of $\$ 750.80$ ? Losses of $\$ 1000$ and $\$ 110.50$ ?

Circle the antecedent in each sentence, and underline the pronoun in parentheses that agrees with it.

Example: Where did your $\boxed{\text{{brothers}}}$ buy (his, $\underline{{their}}$) new skis?

When I saw Oscar and Phina near the soccer field, I called out to (it, them).

A friend speeds by you in her spacecraft at a speed of $0.670 \mathrm{c}$. It is measured in your frame to be $4.80 \mathrm{~m}$ long and $1.35 \mathrm{~m}$ high. How many seconds elapsed on your watch when she saw $20.0 \mathrm{~s}$ pass on hers?

Do wet suits allow a swimmer to swim faster? Researchers measured the speed (in meters per second) of swimmers both with and without a wetsuit. The results of the study are shown in the table. Conduct the appropriate test to determine whether the data suggest that wet suits allow a swimmer to swim faster. Be sure to check all model requirements. Use an $\alpha$=0.05 level of significance. If you reject the null hypothesis, estimate the average difference in speed of the swimmer with the wet suit with 95% confidence.

$$\begin{matrix} \text{Swimmer} & \text{1} & \text{2} & \text{3} & \text{4} & \text{5} & \text{6}\\ \text{Without} & \text{1.49} & \text{1.37} & \text{1.35} & \text{1.27} & \text{1.12} & \text{1.64}\\ \text{Without} & \text{1.57} & \text{1.47} & \text{1.42} & \text{1.35} & \text{1.22} & \text{1.75}\\ \text{Swimmer} & \text{7} & \text{8} & \text{9} & \text{10} & \text{11} & \text{12}\\ \text{Without} & \text{1.59} & \text{1.52} & \text{1.50} & \text{1.45} & \text{1.44} & \text{1.41}\\ \text{With} & \text{1.64} & \text{1.57} & \text{1.56} & \text{1.53} & \text{1.49} & \text{1.51}\\ \end{matrix}$$

How do customers first hear about a new product? A random sample of 200 users of a new product was surveyed to determine the answer to this question. Other demographic data such as age were also collected. The respondents included 50 people under the age of 21 and 90 people between the ages of 21 and 35; the remainder was over 35 years of age. Of those under 21, 60% heard about the product from a friend, and the remainder saw an advertisement in the local paper. One-third of the people in the age category from 21 to 35 saw the advertisement in the local paper. The other two-thirds heard about it from a friend. Of those over 35, only 30% heard about it from a friend, while the remainder saw the local newspaper advertisement. Set up the contingency table for the variables age and method of learning about the product. Is there an association between the consumer’s age and the method by which the customer heard about the new product?

The total number $A(t)$ of known asteroids $t$ years after 1990 can be estimated by

$$A(t)=77(1.283)^t \text {. }$$

a) Identify the year that saw the first 5000 asteroids become known. b)How long does it take for the number of known asteroids to double?

A raft is made of $12$ logs lashed together. Each is $45 \mathrm{~cm}$ in diameter and has a length of $6.5 \mathrm{~m}$. How many people can the raft hold before they start getting their feet wet, assuming the average person has a mass of $68 \mathrm{~kg}$ ? Do not neglect the weight of the logs. Assume the specific gravity of wood is $0.60$.

Rubber tires and wet blacktop have a coefficient of kinetic friction of $0.500$. A pickup truck with mass $75 \overline{0} \mathrm{~kg}$ traveling $30.0 \mathrm{~m} / \mathrm{s}$ skids to a stop. (a) What are the size and direction of the frictional force that the road exerts on the truck?(b) Determine the truck's acceleration. (c) The vehicle would travel how long before stopping.

Usain Bolt set a world record for the $100-\mathrm{m}$ dash on August 1 2009 . If observers on a spaceship moving with a speed of $0.925$ relative to Earth saw Usain Bolt's run and measured his time to $25.21 \mathrm{~s}$, determine the time that was recorded on Earth.