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Tuesday, February 14th. Happy Valentines Day!. Bell Work. Draw a Transverse Wave and label its crest, trough, amplitude, and wavelength. Tuesday, February 14th. Happy Valentines Day! Kinetic Energy & Potential Energy. Goals for Today:.
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Tuesday, February 14th Happy Valentines Day!
Bell Work • Draw a Transverse Wave and label its crest, trough, amplitude, and wavelength.
Tuesday, February 14th Happy Valentines Day! Kinetic Energy & Potential Energy
Goals for Today: • Content Objective: given an object’s mass and velocity, and the equation for Kinetic Energy, you will be able to calculate the object’s KE using THE 4 STPES! • Literacy Objective: You will be able to define kinetic energy and give an example of an object that has some.
Does the Ball have Energy? • When I hold the baseball, does it have energy? • When I drop it, does it have energy when it is falling? • What about when it hits the ground? • Where did that energy come from?
The Baseball had 2 Types of Energy • Potential Energy – stored energy, due to position (above the ground) or condition • Kinetic Energy - energy a moving object has because of its motion • When did the ball have Potential Energy? • When did it have Kinetic Energy?
Kinetic Energy • All moving objects have Kinetic Energy • A moving car, a thrown javelin, a rolling bowling ball, a running horse, someone riding a dirt bike • We can calculate the amount of kinetic energy a moving object has using the equation: KE = ½ * mass * velocity2 KE = ½ m v2
KE = ½ * mass * velocity2 • Kinetic Energy depends on: • MASS • VELOCITY • Kinetic Energy is measured in Joules • “ J ” for short
I’ll use THE 4 STEPS to solve for KE: KE = ½ m v2 • A person riding a dirt bike is traveling at 15 m/s. The weight of the bike and the person total 140 kg. What is their Kinetic Energy (KE)? • Step 1. What Information are we given? • Step 2. What information do we need? • Step 3. What equation will we use? • Step 4. Insert Info and Solve.
Now let’s try Together • A horse is walking around, grazing. He weighs 520 kg and is moving at 2 m/s. What is it’s Kinetic Energy? • Step 1. What Information are we given? • Step 2. What information do we need? • Step 3. What equation will we use? • Step 4. Insert Info and Solve.
Try one in your Groups • You are target shooting, using 9 mm bullets. The bullets weigh 0.115 kg and travel at a velocity of 340 m/s once they’re shot. What is this moving bullet’s Kinetic Energy? • Step 1. What Information are we given? • Step 2. What information do we need? • Step 3. What equation will we use? • Step 4. Insert Info and Solve.
On Your Slip of Paper • 1. Please define Kinetic Energy. Give an example of an object that has Kinetic Energy. • 2. Using THE 4 STEPS, find the Kinetic Energy of a school bus with mass 10,000 kg if it is traveling down Beavercreek Road at 20 meters/second? • --When You Are Done: Flip Paper Over, Remain Quiet, and Relax
A Couple Energy Jokes • Why did the Gardner plant a light bulb? • He hoped to grow a Power Plant! • For this one, know that electricity is measured in a unit called a “Watt” • As Seen on a Sign off Hwy 213: • You Can Trust Our Electricians, We Know Watts Watt.
We Already Introduced Potential Energy, but let’s refresh our brains: • Potential Energy – stored energy, due to position (above the ground) or condition • I’ve found the man with the MOST Potential Energy – a type of energy called Gravitational Potential Energy • http://www.youtube.com/watch?v=e335kbl9YWc&feature=player_embedded
Gravitational Potential Energy • Today we are going to be talking about a type of Potential energy called Gravitational Potential Energy • Gravitational Potential Energy – stored energy by objects due to their position above Earth’s surface
Gravitational Potential Energy • Anything that can fall has stored energy • Amount of Potential Energy depends on: • The object’s mass • How high above the Earth’s surface it is (height) • The equation for GPE GPE= mass *gravity * height GPE = mgh
Climber Man’s GPE • GPE = mass * gravity * height • Let’s Say he weighs 160lbs, which = 80 kg • Gravity is always 9.8 m/s/s • Climber man stood at 1,768 feet at the top. 1,768 ft = 540 meters • GPE = mass * gravity * height • GPE = (80kg)(9.8 m/s/s)(540m) • GPE = 423,360 J
What does 423,360 J really mean? • If Climber Man fell into a 10,000 gallon pool, his 423,360 J would be able to instantly raise the temperature of the 10,000 gallons by 1 degree C!
Comparing Object’s GPE • Let’s compare one student sitting on a stool. • To one student sitting on a text book. • Let’s assume the students have about the same mass • Who has more Gravitational Potential Energy?
Another Comparison • A hiker just summitted Mt. Hood, which stands about 11,000 feet tall. He stands proudly on the snowy mountain ground and poses for a picture. • A second hiker, starting her journey, pulls over in Government Camp and stands on dry, snow-less pavement planning her hike on her map. • Which of the two hikers has more Gravitational Potential Energy?
Other Side of your Slip of Paper • A can of Monster Energy drink is sitting on the top shelf in your refrigerator. Two shelves below is a can of Mountain Dew. • Which of the two energy-filled drinks has the most Gravitational Potential Energy. • Why?