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Calculating Potential and Kinetic Energy. Follow the steps. Equations. Potential Energy (E p )=Weight x Height Or: Kinetic Energy (E k )=1/2 (mass x velocity 2 ) SHOW YOUR WORK FOR EACH STEP. E P. Ht. Wt.
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Calculating Potential and Kinetic Energy Follow the steps
Equations • Potential Energy (Ep)=Weight x Height • Or: • Kinetic Energy (Ek)=1/2 (mass x velocity2) • SHOW YOUR WORK FOR EACH STEP EP Ht. Wt.
Let’s calculate some SIMPLE kinetic energy equations: What is the kinetic energy of a 0.5kg soccer ball that is traveling 3 m/s? Ek = ½ (m x v2) Ek = ½ (.5 x 32) Ek = ½ (.5 x 9) Ek = ½ (4.5) Ek=2.25 J What is the kinetic energy of a 1 kg strawberry pie that is thrown across the lunch room with a speed of 2 m/s? Ek = ½ (m x v2) Ek = ½ (1 x 22) Ek = ½ (1 x 4) Ek = ½ (4) Ek=2 J
A shot putter heaves a 8 kg shot with a velocity of 7.5 m/s. What is the form of energy? ______________ Calculate it. Ek = ½ (m X v2) Ek = ½ (8 x 7.52) Ek = ½ (8 x 56.25) Ek = ½ (450) Ek = 225 A jogger with a mass of 65 kg is traveling at a speed of 2.5 m/s. What is the form of energy? ________________ Calculate it. Ek = ½ (m X v2) Ek = ½ (65 X 2.52) Ek = ½ (65 x 6.25) Ek = ½ (406.25) Ek = 203.125
An apple in a tree has a mass of 45 kg and is hanging in a tree 22 meters above the ground. The apple has _____________ energy. Calculate it. • Ep= Wt. X Ht. • Ep = 45kg x 22m =2025 J • The same apple falls from the tree at 4 m/s. What type of energy is described? _______________ Calculate it. • Ek=1/2 (m x v2) • Ek = ½ (45 x 42) • Ek = ½ (45 x 16) • Ek = ½ (720) • Ek = 360 J
Determine the potential energy of roller coaster that has a first hill of 2000m tall and coaster Cars with a mass of 625 kg. Ep = Wt. x Ht. Ep = 625 x 2000 Ep = 1,250,000 J If the roller coaster is traveling at a speed of 20 m/s at the bottom of the first hill, determine the coaster’s kinetic energy. Ek = ½ (m x v2) Ek = ½ (625 x 202) Ek = ½ (625 x 400) Ek = ½ (250,000) Ek = 125,000 J Thinking question: What would happen to the kinetic energy of the coaster if the mass of the coaster car doubled?
CHALLENGE question! • A bike rider approaches a hill with a speed of 8.5 m/s. The total mass of the rider and the bike is 85 kg. • What is the kinetic energy of the bike and rider? • The rider coasts up the hill. Assuming there is no friction, at what height will the bike come to a stop?