Potential (GPE) and Kinetic (KE) Energy practice

Potential (GPE) and Kinetic (KE) Energy practice

Kinetic Energy

Energy of Motion

• KE = .5 x m x v²

• Energy = Joules

• Weight = Newtons

• Mass = Kilograms

• Velocity = m/s

• Gravitation Acceleration = 9.8 m/s²

Gravitaional Potential Energy

Energy of Position

• PE = mass x gravitational acceleration (9.8 m/s²) x height OR

• Weight x Height

• Newtons = kg m /s²

• Joules (J)= kg m²/s²

• Weight = mass x gravity

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Multiple Choice

Determine whether the object in the following problem has kinetic or potential energy.

You serve a volleyball with a mass of 21 kg. The ball leaves your hand with a speed of 30 m/s. The ball has _____________ energy.

• Potential

• Kinetic

You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. The ball has _____________ energy.

• The ball is in motion, so It has kinetic energy.

• The formula we will use to solve for the amount of kinetic energy is:

• .5 x m x v²

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Solve the problem:

You serve a volleyball with a mass of 2.1 kg. The ball leaves your hand with a speed of 30 m/s. Solve for the amount of Kinetic Energy. (KE = .5 x m x v²)

• Using the formula KE = .5 x m x v² Let's plug in our known values.

• .5 x 2.1 x 30²

• 30² = 900 so...

• .5 x 2.1 x 900 = 945

Multiple Choice

Determine whether the object in the following problem has kinetic or potential energy.

A baby carriage is sitting on a hill that is 21 m high. The carriage with the baby weighs 12 N. The carriage has _________ energy.

• potential

• kinetic

A baby carriage is sitting on a hill that is 21 m high. The carriage with the baby weighs 12 N. The carriage has _________ energy.

• The carriage is not in motion, yet.

• So we say the carriage has potential energy based on it's position at the top of the hill.

• .We will use the formula GPE = Weight x height to solve for the amount of potential energy. GPE = W x h

A baby carriage is sitting on a hill that is 21 m high. The carriage with the baby weighs 12 N. The formula we will use is GPE= weight x height

• GPE = w x h

• GPE = 12N x 21 m = 252

• Energy is measured in Joules, so it would be 252 J

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Multiple Choice

Determine whether the object in the following problem has kinetic or potential energy.

A car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. The car has _____________ energy.

• potential

• kinetic

A car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. The car has _____________ energy.

• Because the car is moving/in motion, we say it has kinetic energy.

• The formula we will use to solve is

• KE = .5 x m x v²

A car is traveling with a velocity of 40 m/s and has a mass of 1120 kg. Let's solve for the kinetic energy of the car.

• KE= .5 x m x v²

• Let's plug in the values that we know.

• KE = .5 x 1120 x 40²

• KE = .5 x 1120 x 1600

• KE = 896000 Joules

Multiple Choice

Determine whether the object in the following problem has kinetic or potential energy.

A cinder block is sitting on a platform 20 m high. It weighs 79 N. The block has _____________ energy.

• potential

• kinetic

A cinder block is sitting on a platform 20 m high. It weighs 79 N. The block has _____________ energy.

• The block is not moving therefore it has potential energy.

• Use the formula GPE = Weight x height

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Let's Solve!

A cinder block is sitting on a platform 20 m high. It weighs 79 N. Solve for the potential energy of the block.

• GPE = weight x height

• GPE = 20 x 79 = 1580 J

Multiple Choice

Determine whether the object in the following problem has kinetic or potential energy.

There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N. The bell has _____________ energy.

• potential

• kinetic

There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N. The bell has _____________ energy.

• The bell is not moving therefore it has potential energy

• Use the formula GPE = weight x height

There is a bell at the top of a tower that is 45 m high. The bell weighs 190 N. Let's solve!

• The formula for GPE = weight x height

• Plug in known values.

• GPE = 45 x 190

• GPE = 8550 J