Energy—Day 9 Materials Needed: Writing Utensil Folder Notebook Please pick up the handout on the front table!

B ELL WORK & AGENDA DAY 9 1. How do energy conversions take place in roller coasters? 2. A 0.15 kg ball is thrown into the air and rises to a height of 20 m. How much kinetic energy did the ball initially have? Agenda: * BLAM * Review for the test

Q1: T HE CHART BELOW SHOWS HOW MANY DAYS IT TOOK A SEED TO SPROUT AT THREE DIFFERENT TEMPERATURES. B ASED ON THE CHART, HOW LONG WILL IT TAKE FOR THE SAME KIND OF SEED TO SPROUT AT 75°F? A. 11 days B. less than 11 days C. more than 11 days D. the number of days cannot be predicted SC8.1.1.g DOK 3 TemperatureDays Needed to Sprout 60° F15 65° F13 70° F11

Q2: W HAT PROPERTY OF LIGHT WAVES CAN BE OBSERVED AS LIGHT WAVES PASS FROM ONE MEDIUM TO ANOTHER AND CHANGE SPEED ? A. diffraction B. reflection C. refraction D. separation SC8.2.3.b DOK 1

M ATH BOOSTER D AY 9 The average rocket can reach speeds of 25,000 miles per hour. Convert that speed into kilometers per second. Use 1 mile = 1.6 kilometers Math Talk: Explain HOW you solved this problem.

G REEK & L ATIN D AY 9 Greek /LatinPicture meter axi goni leg oper

O BJECTIVE D AY 9 I will know the definitions and concepts of work, power, and energy. I will be able to mathematically solve story problems involving work, power, and energy.

B ELL WORK DAY 9 -- ANSWERS 1. How do energy conversions take place in roller coasters? Answer: When the roller coaster is at a certain height it has potential energy and when its rolls down, the potential energy changes to kinetic energy. The total (Mechanical Energy) remains the same. 2. A 0.15 kg ball is thrown into the air and rises to a height of 20 m. How much kinetic energy did the ball initially have? Answer: All the kinetic energy got converted into gravitational potential energy. Givens: 0.15 kg 20 m = h know g = 9.8 m/s 2 Unknown: KE Equation: KE = PE = mgh Plug in numbers: = (0.15 kg)(9.8 m/s 2 )(20 m) Answer:= 29.4 joules

A1: T HE CHART BELOW SHOWS HOW MANY DAYS IT TOOK A SEED TO SPROUT AT THREE DIFFERENT TEMPERATURES. B ASED ON THE CHART, HOW LONG WILL IT TAKE FOR THE SAME KIND OF SEED TO SPROUT AT 75°F? A. 11 days A s temperature increases, the days needed to sprout decreases so at 75°F the plant would sprout in less than 11 days. B. less than 11 days A s temperature increases, the days needed to sprout decreases so at 75°F the plant would sprout in less than 11 days. C. more than 11 days A s temperature increases, the days needed to sprout decreases so at 75°F the plant would sprout in less than 11 days. D. the number of days cannot be predicted A s temperature increases, the days needed to sprout decreases so at 75°F the plant would sprout in less than 11 days. SC8.1.1.g DOK 3 Temperat ure Days Needed to Sprout 60° F15 65° F13 70° F11

A2: W HAT PROPERTY OF LIGHT WAVES CAN BE OBSERVED AS LIGHT WAVES PASS FROM ONE MEDIUM TO ANOTHER AND CHANGE SPEED ? A. diffraction Diffraction is the bending of waves around barriers or through openings. B. reflection Reflection happens when light bounces off an object. C. refraction Refraction is the bending of a wave as it passes at an angle from one substance, or material, to another. D. separation White light can be separated into different colors during refraction. SC8.2.3.b DOK 1

M ATH BOOSTER D AY 9 The average rocket can reach speeds of 25,000 miles per hour. Convert that speed into kilometers per second. Use 1 mile = 1.6 kilometers x 1.6 ÷ 60 ÷ 60 = MPH ≅ 11.1 KPS Math Talk: First set up the different ratios that are being used. Since we need to get to Kilometers per second, those need to be in the ratios. Once the ratios are established, all numbers above the line are multiplied, and all numbers below the line are divided miles1.6 kilometers1 hour1 minute 1 hour1 mile60 minutes60 seconds

1. How are work and energy related? a. Energy is the rate of doing work. b. Work is a form of energy. c. Work is the transfer of energy. d. Energy is created by work. ANS:C Work is the transfer of energy.

2. A moving object with a mass of 10 kg has 320 J of kinetic energy due to its motion. How fast is the object moving? a) 8 m/s b) 10 m/s c) 32 m/s d) 64 m/s

2. A moving object with a mass of 10 kg has 320 J of kinetic energy due to its motion. How fast is the object moving? a) 8 m/s b) 10 m/s c) 32 m/s d) 64 m/s Givens: 10 kg = m 320 J = KE Unknown: v Equation: KE = ½ mv 2 Plug in numbers: 320 J = ½ (10 kg)(v 2 ) Answer: 8 m/s (A)

3. Which of these is an example of elastic potential energy? a. a bow prepared to release an arrow b. a rubber ball thrown into the air c. a book about to fall from a table d. a truck pulling a trailer ANS:A

4. A small airplane and a helicopter have identical masses. If the airplane’s altitude compared to the ground is three times that of the helicopter, how much more gravitational potential energy does the airplane have than the helicopter? a) times as much b) 3 times as much c) 6 times as much d) 9 times as much ANS: B – linear relationship

5. The energy stored in the bonds between atoms of a compound is what kind of energy? a) atomic b) chemical c) electromagnetic d) thermal ANS:B

6. You lift a book from the floor to a bookshelf 1.0 m above the ground. How much power is used if the upward force is 15.0 N and you do the work in 2.0 s? Givens: 1.0 m = d 15.0 N = F 2.0 s = t Know: g = 9.8 m/s 2 Unknown: P Equations: W = Fd P = W ÷ t P = Fd ÷ t Plug in numbers: P = (15 N)(1.0 m) ÷ (2.0 s) Answer: = 7.5 W

I NDEPENDENT WORK D AY 9 Students will do the review worksheet.

Finish the review sheet.

1. Give an example in which the potential energy changes to kinetic energy and vice versa. 2. Describe how energy can be converted from one form to another in a wind-up toy. 3. Describe the energy of a playground swing at its highest position.