Mechanical energy

Question 1

Energy is …

Answer 1

A measure of a systems ability to do work.
Symbol: E
Units: Joules (J)

Question 2

What are the two main groupings of energy?

Answer 2

Potential and Kinetic

Question 3

What is the definition of Gravitational potential energy?

Answer 3

The energy due to it’s position in a gravitational field relative to some reference point.
Symbol: Ep
Unit: Joules (J)

Question 4

Gravitational potential energy is the energy of an object due to its …

Answer 4

Gravitational potential energy is the energy of an object due to its height above the Earths surface.

Question 5

The greater the height above the Earths surface, and the greater the mass the … the gravitational potential energy.

Answer 5

greater

Question 6

What is the equation to find gravitational potential energy?

Answer 6

Ep = m x g x h

mass times gravitational acceleration (9.8m.s^-2) times height.

Question 7

Definition of Kinetic energy.

Answer 7

Kinetic energy is the energy an object, with mass, has due to its motion.
Symbol: Ek
Unit: Joules (J)

Question 8

What is the equation to find Kinetic energy?

Answer 8

Ek = 1/2 x m x v^2

half mass times speed squared.

Question 9

The slower an object is moving and the lesser the mass the … kinetic energy it will have.

Answer 9

less

Question 10

What is mechanical energy?

Answer 10

The sum of gravitational potential energy and kinetic energy of a system.
Symbol: Em or Emech
Emech = Ep + Ek

Question 11

What is the law of conservation of energy?

Answer 11

Energy cannot be created or destroyed, just transformed from one form into another or transferred form one object to another.

Question 12

Term for this definition:

The total mechanical energy of an isolated system that experiences only conservative internal forces is conserved.

Answer 12

The principle of Conservation of Mechanical Energy.

Question 13

T/F:
Eki + Epi = Ekf + Epf
Eki - Ekf = Epf - Epi

Answer 13

TRUE Learn!!!

TRUE Learn!!!

Question 14

T/F:

If kinetic energy increases then potential energy decreases by the same amount, and vice versa.

Answer 14

TRUE Learn!!!

Question 15

Term for this definition:
When the only force acting on them is the force due to gravity.
T/F:
Only possible if an object is moving towards the surface of the Earth.
These experiments can occur in anyone’s backyard.
Objects that are free-falling will have their mechanical energy conserved.

Answer 15

Objects in free fall, free falling.
False, objects rising can be free falling if there are no exterior forces.
False, can only occur in a vacuum, no air resistance.
True.

Question 16

In an example of a pendulum and a roller coaster answer the following questions.
T/F
Energy is conserved.
Em1 = Em2.
Potential energy at top is Max Ep.
Kinetic energy at top is Min Ek. 
Potential energy at bottom is Min Ep.
Kinetic energy at bottom is Max Ek.

Answer 16

True
True
True
True
True
True

Question 17

State the principle of conservation of mechanical energy.

Answer 17

In an isolated system, the total mechanical

energy remains constant.