Conservation of Energy

As an object is falling, its ___ energy turns into ___ energy.

• Gravitational Potential ; Kinetic

• Kinetic ; Gravitational Potential

• Thermal ; Kinetic

• Total ; Potential

A frictionless pendulum is swinging back and forth. Where does the pendulum have the least kinetic energy?

• At its highest point.

• At its lowest point.

• Half-way between the highest and lowest point

• It has the same Kinetic energy all the time

Tags

NGSS.MS-PS3-1

NGSS.MS-PS3-5

A frictionless pendulum is swinging back and forth. Where will the pendulum have the most TOTAL energy?

• At its highest point.

• At its lowest point.

• Half-way between the highest and lowest point.

• It has the same total energy all the time

A book has 200J of potential energy and then it falls onto the floor. After it hits the floor it is sitting still and contains no kinetic or potential energy, what happened to the energy?

• It was destroyed.

• It goes into the floor and book as thermal energy and sound.

• It changes to chemical potential energy.

• It turns into gravity.

Tags

NGSS.HS-PS3-4

Students conducted a pendulum experiment to demonstrate the conservation of energy principle. Below is a diagram showing the pendulum at different points of its swing. Which letter/s on the diagram would correspond to the point/s of the pendulum’s swing where there would be both potential and kinetic energy?

• A & E only

• B & D

• C only

• All points have both Kinetic and Potential

Tags

NGSS.MS-PS3-4

NGSS.MS-PS3-5

A student drops a bouncy ball from a height of 3m in her physics lab. How high will the ball bounce back up and why?

• 3m because the kinetic energy is greater than the potential energy

• 3m because the potential energy will be the same

• Less than 3m because some of the starting energy is transferred into the earth

• Greater than 3m because the ball creates energy when it bounces

Tags

NGSS.MS-PS3-2

NGSS.MS-PS3-5

The skateboarder shown above has a potential energy of 2,800 J and kinetic energy of 0J at a height of 4 meters. How much total mechanical energy will she have after 2 seconds?

• 2000J

• 1600J

• 1400J

• 2800J

Tags

NGSS.HS-PS3-1

What is the formula for total mechanical energy?

• KE + PE = TME

• TME = 1/2 * mv

• TME = mgh

• TME= 1/2mv² - mgh

Tags

NGSS.HS-PS3-2

If the skateboarder has 2000J of PE and 0J of KE at 4m, how much KE would she have at 2m high?

• 2000J

• 800J

• 1000J

• 0J

Tags

NGSS.MS-PS3-2

NGSS.MS-PS3-4

NGSS.MS-PS3-5

What are two ways that the law of energy conservation can appear to be broken

• Gravity turning an object's potential energy into kinetic energy

• Energy being transferred from one object to another object that is "outside" of the system

• Energy transforming into other forms that are difficult to measure such as heat and sound.

• When collisions destroy energy.

Tags

NGSS.MS-PS3-5