Science 8.2

Speed, Velocity, and Acceleration

You've probably noticed by now that there are tons of words we use every day, like "theory", "energy", and "work" that have very specific meanings in science. Well, here are a few more! Motion, speed, velocity, and acceleration are all words you know, but they have more specific meanings in physics we need to understand. Watch this video to find out more. Then, when you're finished, read about these concepts in a bit more detail below.

Velocity Reading

Unfortunately, since we're not doing in-person class, we can't conduct some experiments to help you get a "hands-on" understanding of these concepts. But you can play around with this tool that may help you get an understanding of velocity! As you mess around with the car, pay attention to the graphs (vectors) and see how speed over time is represented.

Email me your answers!

iolson@tacomacommunityhouse.org

1.) What is the difference between speed and velocity?

2.) Define acceleration. What does it mean besides an increase in speed?

3.) What if the graph showed acceleration rather than speed? Where would the line be when the car was continuing at a constant speed of 40 mph in the same direction? Where would the line be if the speed were continually increasing? Decreasing?

4.) An object, such as a planet, circling another object, such as the Sun, at a constant speed is said to be accelerating. Explain why this motion is an example of acceleration.

Read the three texts below for information about motion, speed, and acceleration. These are important because they will give you the formulas for solving problems. You will most likely see problems requiring these formulas on the GED test. (However, you don't need to memorize the formulas. They will give them to you while you take the test).

Motion

Speed and Velocity

Acceleration

And here are some videos with some step-by-step examples

Solve the following problems. To solve each, write the equation that will be used. Work out the problem by replacing the words in the equation with the number values from the word problem. Finish by solving for the answer. Be sure to give answer with correct units.

Average Speed

Use the following equation to calculate speed:

Average Speed = Total Distance Total / Time Examples:

1. A plane travels 1000 miles in 5 hours. What is the plane’s average speed?

Equation: s=d/t

s=1000 miles/ 5 hours

200 miles per hour

2. A plane travels 550 miles/hour in 4 hours. How far did the plane travel? Equation: d=s * t

3. A girl on a bicycle rides down a hill 500 meters long in 50 seconds. What is the girl’s speed?

4. A car moving at a uniform speed travels 32 miles in 0.5 hours. What is the speed of the car? Express your answer in miles per hour.

5. If a marathon runner runs an average speed of 11 miles/hour for three hours. How far did the runner run in in the three hours?

Answers

2. A plane travels 550 miles/hour in 4 hours. How far did the plane travel?

Answer: d=s * t

d=550 miles/hour * 4 hours = 2200 miles

3. A girl on a bicycle rides down a hill 500 meters long in 50 seconds. What is the girl’s speed?

s=d/t

s=500 meters/ 50 seconds = 10 meters per second

4. A car moving at a uniform speed travels 32 miles in 0.5 hours. What is the speed of the car? Express your answer in miles per hour.

s=d/t

s=32 miles/ .5 seconds = 16 miles per hour

5. If a marathon runner runs an average speed of 11 miles/hour for three hours. How far did the runner run in in the three hours?

d=s * t

d=11 miles/hour x 3 hours = 33 miles

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