Problem: Article: You can calculate the average acceleration of an object over a period of time based on its velocity (its speed traveling in a specific direction), before and after that time. To do this you need to know equation for acceleration: a = Δv / Δt where a is acceleration, Δv is the change in velocity, and Δt is the amount of time it took for that change to occur.  The unit for acceleration is meters per second per second or m/s2. Acceleration is a vector quantity, meaning it has both a magnitude and a direction. The magnitude is the total amount of acceleration whereas the direction is the way in which the object is moving. If it is slowing down the acceleration will be negative. You can further define Δv and Δt:  Δv = vf - vi and  Δt = tf - ti where vf is the final velocity, vi is the initial velocity, tf is the ending time, and ti is the starting time.  Because acceleration has a direction, it is important to always subtract the initial velocity from the final velocity. If you reverse them, the direction of your acceleration will be incorrect. Unless otherwise stated in the problem, the starting time is usually 0 seconds. First write down your equation and all of the given variables. The equation is a = Δv / Δt = (vf - vi)/(tf - ti). Subtract the initial velocity from the final velocity, then divide the result by the time interval. The final result is your average acceleration over that time.  If the final velocity is less than the initial velocity, acceleration will turn out to be a negative quantity or the rate at which an object slows down. Example 1: A race car accelerates uniformly from 18.5 m/s to 46.1 m/s in 2.47 seconds. What is its average acceleration?  Write the equation: a = Δv / Δt = (vf - vi)/(tf - ti)  Define the variables: vf = 46.1 m/s, vi = 18.5 m/s, tf = 2.47 s, ti = 0 s. Solve: a = (46.1 – 18.5)/2.47 = 11.17 meters/second2.   Example 2: A biker traveling at 22.4 m/s comes to halt in 2.55 s after applying brakes. Find his deceleration.  Write the equation: a = Δv / Δt = (vf - vi)/(tf - ti)  Define the variables: vf = 0 m/s, vi = 22.4 m/s, tf = 2.55 s, ti = 0 s. Solve: a = (0 – 22.4)/2.55 = -8.78 meters/second2.
Summary: Define the equation for average acceleration. Understand the variables. Use the formula to find acceleration.

In one sentence, describe what the following article is about: While beer is okay for most people in moderation, it can cause a variety of problems if you drink too much of it. Long-term overuse of beer can lead to obesity, problems with the heart, liver, pancreas, and digestive tract, and neurological problems. When consumed by a pregnant or nursing mother, beer can be harmful to a fetus or breastfed baby. Excessive drinking can also impair your judgment, damage your relationships, and leave you feeling tired and sick. If you are considering reducing or eliminating your beer consumption, you may find it helpful to identify some of the reasons you want to stop drinking beer.  If you are concerned that drinking too much beer may be affecting your health, talk to your doctor about it. Your doctor may be able to give you a better idea about what sort of effect the alcohol you consume is having on your body. Consider whether the amount of beer you are drinking may be affecting your work or your relationships. Are you having arguments with your family, friends, or significant other(s) because of the amount of beer you drink? Are you often too tired to get work done because you had too much beer the night before? Once you have identified some of your reasons for wanting to stop drinking beer, you might find it helpful to write them down. You may wish to ask a supportive friend or family member to sit down with you and help you come up with your list. Depending on how much beer you drink and how dependent you are on beer, you may need to quit gradually rather than just stopping abruptly. Quitting cold turkey may result in potentially serious withdrawal symptoms. Your doctor can assess your overall health and help you come up with a plan that works best for you.  Depending on your health and how alcohol-dependent you are, your doctor may recommend quitting beer altogether, quitting for a specific period of time (e.g. 30 days), or simply reducing your beer intake. Bring up any questions and concerns you may have about how drinking beer is affecting your health. Once you have discussed a possible course of action with your doctor, write up the steps you intend to take to stop drinking beer. Make a few copies of the plan and post them around in places where you will see them every day, like on the door of your refrigerator or on your bathroom mirror.  Make a list of strategies that you will use to keep yourself on track, e.g. avoiding going to the bar with friends after work, getting all the beer out of your house, or filling your regular drinking time with some other activity. Include a list of possible obstacles to carrying out your plan, and strategies for dealing with these obstacles. If you have decided to scale back your use of beer gradually, include a timeframe for reducing your beer drinking in your plan (e.g., cut back to two glasses a day the first week, one glass per day in the second week, and so on). Make note of any relapses, but also keep track of your successes. When the period of your plan ends, evaluate how you did and revise your plan if necessary. Then, keeping the things you learned in mind, try again. Tell people that you know will be supportive. This may include family, close friends, or your doctor. They can help keep you accountable and take steps to support your efforts.
Summary:
Decide why you want to stop drinking beer. Make a list of the reasons you want to stop drinking. Talk to your doctor about the best way to quit. Write a plan and put it where you will see it. Keep track of your progress. Tell people you trust about your plan.