Block _____ Name ________________________________________ Date __________

Average Speed
1. In the 2008 Summer Olympics, Usain Bolt won the 100-m race in 9.69 s. What was his average speed?
2. Light from the sun reaches Earth in 8.3 min. The speed of light is 3.0108 m/s. How far is Earth from the sun?
3. In Major League Baseball, the distance between the pitcher’s mound and home plate is 18.5 m. On September 24, 2010, Aroldis Champman threw a 105-mph fastball. How much time (in s) does the take to get to homeplate?
4. A high school athlete runs 100 m in 12.2 s. What is the athlete’s average speed?
5. Suppose a car travels at a constant speed of 25 mph. How far would it move in (a) 1 hour (b) 1 minute (c) 1 second?
6. To establish the world record for the fastest jet-engined car, the car must travel a distance of 604 m in one direction then travel the same distance in the opposite direction. The first run took 2.12 s and the second run took 2.15 s. (a) What was the average speed for the first run? (b) What was the average speed for the second run?
7. You are driving down a street at 35 mph. Suddenly a child runs into the street in front of you. It takes you 0.75 s to react and slam on the brakes. How many meters do you travel before you begin to slow down?
8. If you drive at 55 mph, how long will it take you to travel from Norfolk to Nags Head N.C., 81.6 miles?
9. If a migrating bird can average 25 mph, how far can this bird travel in 3 weeks? Assume that the bird flies 12 hours per day.
10. A football player runs with an average speed of 9.52 m/s. How much time does it take him to cover 40 yards?
11. If a plane can travel at a speed of 270 mph, how much time will it take to go 852 miles?
12. On the interstate, you pass the 5-mile marker at 9:00 am. At 9:30 am, you pass the 32-mile marker. What is your average speed?
13. In a particle accelerator, an electron can travel at 90% of the speed of light. How far can an electron travel in the blink of eye, 0.9 s?
14. You walk four and a half times around a circular track in 1 hour. The radius of the track is 200 meters. What was your average speed (in m/s)?

Ever heard of D = v*t?

Try using it.

You won't learn any physics if you have others do all your work.

1. To find Usain Bolt's average speed, you need to divide the distance he ran (100 m) by the time it took him to run that distance (9.69 s). So, average speed = distance / time. Plug in the values: average speed = 100 m / 9.69 s.

2. To find the distance between Earth and the sun, you need to multiply the speed of light (3.0108 m/s) by the time it takes for light to reach Earth from the sun (8.3 min). First, convert minutes to seconds: 8.3 min × 60 s/min = 498 s. Then, multiply the speed of light by the time: distance = speed × time.

3. To find the time it takes for Aroldis Champman's fastball to reach home plate, you need to convert 105 mph to m/s. 1 mph is approximately 0.447 m/s. Multiply 105 mph by 0.447 to convert it to m/s. Then, divide the distance (18.5 m) by the speed to get the time: time = distance / speed.

4. To find the athlete's average speed, divide the distance (100 m) by the time it took to run the distance (12.2 s): average speed = distance / time.

5. To calculate the distance the car travels, you need to multiply the speed (25 mph) by the time. Note that you'll need to convert hours to seconds, minutes, and seconds for each part:
(a) The distance traveled in 1 hour is 25 mph × 1 hour × 1 minute × 1 second.
(b) The distance traveled in 1 minute is 25 mph × 1 minute × 1 second.
(c) The distance traveled in 1 second is 25 mph × 1 second.

6. To find the average speed for each run, divide the distance (604 m) by the time it took for each run. For the first run, average speed = distance / time (2.12 s). For the second run, average speed = distance / time (2.15 s).

7. To find the distance traveled before slowing down, you need to calculate the distance covered in 0.75 s at a speed of 35 mph. First, convert 35 mph to m/s by multiplying it by 0.447. Finally, multiply the speed (in m/s) by the time (in seconds) to get the distance traveled.

8. To find the time it will take to travel from Norfolk to Nags Head, divide the distance (81.6 miles) by the speed (55 mph). The time taken is equal to distance / speed.

9. To find the distance the bird can travel in 3 weeks, we need to multiply the average speed (25 mph) by the time the bird flies each day (12 hours) and the number of days (21 days).

10. To find the time it takes for the football player to cover 40 yards, you need to divide the distance (40 yards) by the average speed (9.52 m/s). First, convert yards to meters (1 yard = 0.9144 m).

11. To find the time it takes for the plane to go 852 miles, divide the distance (852 miles) by the speed (270 mph).

12. To find the average speed, divide the total distance traveled (32 miles - 5 miles) by the time taken (30 minutes or 0.5 hours).

13. To find the distance the electron can travel in 0.9 s, multiply the speed of light (0.9 × 3.0108 m/s) by the time (0.9 s).

14. To find your average speed walking around a circular track, you need to find the total distance covered by multiplying the circumference of the track (2π × radius) by the number of times you walked around (4.5 times) in 1 hour. Finally, divide the total distance by the time (1 hour) to get the average speed.