Conservation of energy lesson

Law of Conservation of Energy

• Energy can be neither created

nor destroyed by ordinary
means.

• Energy Can be transformed or

transferred from one form to
another.

• The total amount of energy is

the same before and after any
transformation or transfer.

Multiple Choice

According to the law of Law of Conservation of Energy

• Energy can be neither created nor destroyed by ordinary means

• Energy can be created, but it cannot be destroyed

• Energy cannot be created, but it can be destroyed

An objects’ energy can be:

All Kinetic Energy

All Potential Energy

A combination of both

Multiple Select

Any object can have________

Choose all correct answers

• All Kinetic energy

• All potential energy

• A combination of KE and PE

• Kinetic energy only in all circumstance

•AS velocity increases kinetic energy increases and

potential energy decreases

•As velocity decreases kinetic Energy decreases and

potential energy increases

Multiple Choice

•AS velocity ________ kinetic energy increases and potential energy decreases

• increases

• decreases

• does not change

Example
As a basketball
player throws
the ball into the
air, various
energy
conversions
take place.

Multiple Choice

A small frog jumps over a rock of height 15 cm.

Which of the following statements is true about its motion

• The potential energy of a frog is constantly changing during a jump. It is zero at the moment the frog jumps and increases until the frog reaches its maximum height

• The potential energy of a frog is constantly changing during a jump. It is maximum at the moment the frog jumps and decreases until the frog reaches zero at the maximum height

Equations

• 𝑀𝐸 = 𝐾𝐸 + 𝑃𝐸

• 𝑀𝐸𝑖 = 𝑀𝐸𝑓

• 𝐾𝐸𝑖 + 𝑃𝐸𝑖 = 𝐾𝐸𝑓 + 𝑃𝐸𝑓

ME: mechanical energy

KE: kinetic energy

PE: Potential energy

Multiple Choice

What is the velocity at point A?

• 37 m/s

• Zero

• Cannot be calculated

Multiple Choice

Calculate the mass at point A?

• 37 kg

• Zero

• 51 kg

Multiple Choice

PE at point B is _______

• 20,000 J

• 35,000 J

• 30,000 J

Multiple Choice

KE at point C= _______

• 20,000 J

• 35,000 J

• zero

Multiple Choice

The height at point C= _______

• 15 m

• 30 m

• 10 m

Multiple Choice

Velocity at point C _______

• 37 m/s

• Zero

• 51 m/s

Multiple Choice

PE at point D= _______

• 20,000 J

• 30,000 J

• Zero

Multiple Choice

PE at point E= _______

• 20,000 J

• 30,000 J

• Zero