AKS 5a. 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 Kinetic energy all the time

A book has 200J of potential energy and then it falls onto the floor. After it hits the floor and is sitting still, what happened to the energy?

• It has disappeared.

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

• It changes to chemical potential energy.

• It turns into gravity.

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

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 converted to thermal and sound energy.

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

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.HS-PS3-1