Lesson 1
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Random
You Get What You Get
100

Scientists define energy as which of the following?

  1. A type of matter that fills space
  2. A force that opposes motion
  3. The ability to cause changes in matter

C. The ability to cause changes in matter

100

Which statement best explains why a moving bowling ball can make pins scatter?

  1. Energy is created by the ball at impact, giving the pins motion from nothing.
  2. The pins create kinetic energy when touched and push themselves away.
  3. Kinetic energy carried by the ball is transferred to the pins during the collision, causing them to move.

C. 

Kinetic energy carried by the ball is transferred to the pins during the collision, causing them to move.

100

A balloon-powered boat stores energy as the balloon inflates and then moves forward when released. Which energy transformation sequence best explains this motion?

  1. Thermal energy transforms into electrical energy powering the boat motor
  2. Elastic potential energy transforms into kinetic energy of air and boat motion
  3. Gravitational potential energy transforms directly into chemical energy in the balloon rubber

B — As the balloon stretches, elastic potential energy is stored. When released, this energy drives air out, imparting kinetic energy to the air and exerting a force that produces the boat’s kinetic energy until dissipative forces slow it. Thermal-to-electrical conversion via a motor is not part of the scenario. Gravitational potential converting to chemical in rubber is not correct. Nuclear potential and light pressure are unrelated to the described toy.

100

A system is defined to study a pogo stick in use. Which choice most accurately identifies inputs and outputs for this system?

  1. Input: mass entering the system; Outputs: mass leaving the system.
  2. Input: light from the Sun; Outputs: chemical energy stored in the spring
  3. Input: energy from the person compressing the spring; Outputs: the rider’s upward motion and thermal/sound energy due to friction.

C 

Input: energy from the person compressing the spring; Outputs: the rider’s upward motion and thermal/sound energy due to friction.

100

Which statement best explains why a pendulum released from just in front of a student's face will not swing back and hit the face?

  1. Energy is conserved, and some energy is transferred to the surroundings each swing, so the pendulum cannot return to a position higher than its release point.
  2. The string shortens during motion, so the pendulum's path becomes smaller.
  3. Gravity shuts off at the highest point, stopping the pendulum early.

A.

Energy is conserved, and some energy is transferred to the surroundings each swing, so the pendulum cannot return to a position higher than its release point.

200

Which situation is the best example of an energy transformation primarily from electrical energy to electromagnetic energy?

  1. Dropping a ball from a height to make a sound on impact
  2. Stretching a rubber band and releasing it
  3. Turning on a lamp to produce visible light

C.

Turning on a lamp to produce visible light

200

Two balls roll at the same speed. One has more mass. Which has greater kinetic energy, and why?

  1. The more massive ball, because kinetic energy increases with mass when speed is the same.
  2. They have equal kinetic energy, because speed alone determines kinetic energy.
  3. Neither has kinetic energy until a collision occurs.

A

The more massive ball, because kinetic energy increases with mass when speed is the same.

200

Which statement best distinguishes criteria from constraints in a design problem?

  1. Criteria are the materials list; constraints are the decoration options
  2. Criteria are fixed; constraints can be ignored if the idea is exciting
  3. Criteria describe desired features of success; constraints are the limitations that must be respected

C  — Criteria state what makes a solution successful (for example, transforms potential energy into kinetic energy, is fun, is reusable). Constraints limit how a solution can be built or used (for example, only provided materials, safety). Equating criteria with a materials list confuses a success measure with a resource. Calling criteria only safety rules omits broader goals. Saying constraints can be ignored undermines the definition of mandatory limits. 

200

Why can’t an overbalanced-wheel perpetual motion machine run forever, even if carefully built?

  1. Unavoidable energy losses to sound and heat due to friction remove energy from the system over time.
  2. Mass in the spokes gradually disappears, reducing the torque to zero.
  3. Energy can be created but only during the first rotation, not later ones.

A. 

Unavoidable energy losses to sound and heat due to friction remove energy from the system over time.

200

Which scenario best illustrates conservation of energy during an everyday process?

  1. A roller coaster car rises to the first peak with an initial energy input and then never reaches a higher point because energy is transferred to the surroundings as it moves.
  2. A battery creates energy from nothing to power a flashlight indefinitely without loss.
  3. A moving car gains kinetic energy with no change to any other object or the environment.

A — Once the car has an initial input of energy, it transforms energy between potential and kinetic while transferring some to the surroundings (e.g., thermal, sound). By conservation, without added input it cannot exceed the initial peak height. Energy does not disappear at the top and reappear at the bottom; it transforms and transfers. A battery does not create energy from nothing; it transforms stored chemical energy and depletes. A moving car gains kinetic energy only if energy is transferred from fuel or another source; it cannot increase with no change elsewhere.

300

A ball of mass 2 kg moves at a speed of 3 m/s. What is its kinetic energy? (1/2 Mass x Speed x Speed)

  1. 12 J
  2. 9 J
  3. 18 J

B.

(1/2) 2 x 3 x 3

1 x 3 x 3 = 9

300

A cup at the bottom of a ramp is pushed by balls released from different heights. What change most directly increases how far the cup moves?

  1. Using a lighter ball from the same height to reduce contact time.
  2. Releasing the same ball from a greater height to increase its speed and kinetic energy at the bottom.
  3. Shortening the ramp so the ball travels a smaller distance before impact.

B. 

Releasing the same ball from a greater height to increase its speed and kinetic energy at the bottom.

300

When optimizing a device that already meets all criteria within constraints, which action is most appropriate?

  1. Propose a change based on scientific reasoning, then retest to verify all criteria and constraints are still met
  2. Stop testing, since meeting criteria once shows the design cannot be improved further
  3. Add components beyond allowed materials to boost performance temporarily

 A — Optimization involves making reasoned modifications to improve performance and then retesting to ensure the design continues to satisfy criteria and constraints. Stopping testing prevents improvement verification. Adding unallowed materials violates constraints. Focusing only on subjective features neglects measurable criteria and does not ensure overall performance gains.

300

In the domino scenario where each falling domino topples a larger one, which explanation best fits how a small initial push can topple a much larger domino later in the sequence?

  1. Only the first few dominoes transfer energy; the largest falls due to gravity alone without input.
  2. Energy is transferred and transformed from domino to domino, and with proper spacing and design, each domino’s fall provides enough energy to tip the next larger one.
  3. The initial push stores unlimited energy in the line, so losses do not matter.

B

Energy is transferred and transformed from domino to domino, and with proper spacing and design, each domino’s fall provides enough energy to tip the next larger one.

300

Which statement best distinguishes kinetic energy from potential energy?

  1. Kinetic energy is stored in fields, while potential energy is only in moving particles.
  2. Kinetic energy exists only in waves, while potential energy exists only in solids.
  3. Kinetic energy is associated with motion, while potential energy is associated with position, condition, or chemical composition.


C. Kinetic energy refers to energy due to motion (of objects, particles, waves), while potential energy refers to stored energy related to position in fields, elastic deformation, or chemical bonds. Saying kinetic energy is stored in fields and potential is only in moving particles swaps concepts. Restricting kinetic to waves and potential to solids is incorrect. Depending only on mass for kinetic and only on speed for potential contradicts definitions and equations. 

400

Which list correctly matches each form of energy with a brief description?

  1. Sound energy: position in a gravitational field; Thermal energy: potential energy of a spring; Electrical energy: mass times speed
  2. Sound energy: vibration of particles; Thermal energy: total kinetic energy of particles; Electrical energy: moving electric charges
  3. Sound energy: stored in chemical bonds; Thermal energy: energy in a magnetic field; Electrical energy: energy due to height

B.  — Sound involves particle vibrations in a medium. Thermal energy is the total kinetic energy of particles in a substance. Electrical energy involves moving electric charges in a circuit or natural phenomena like lightning. Assigning chemical bonds to sound, magnetic fields to thermal, or gravitational position to sound mixes up definitions. Claiming still particles for thermal ignores that particle motion is essential. Other pairings confuse light with sound or potential with kinetic forms incorrectly. 

400

In a Newton’s cradle, one raised sphere is released and strikes a row of stationary spheres. Immediately after the first collision, which energy change within the system is observed?

  1. Chemical energy in the spheres transforms directly into thermal energy without motion.
  2. Electrical energy is generated inside the spheres and powers the motion.
  3. Kinetic energy is transferred from the moving sphere to the next sphere, which then swings upward to gain gravitational potential energy.

C. 

Kinetic energy is transferred from the moving sphere to the next sphere, which then swings upward to gain gravitational potential energy.

400

Describe an energy transfer from the Marble Run design challenge and where it took place in the system. 

Kinetic -  Potential (launcher)

Potential - Kinetic (the rest of the marble run)

400

Consider the table: Ball A and Ball B have the same mass, but Ball B moves faster; Ball C has greater mass than A and B and moves at the same speed as B. Which ball has the greatest kinetic energy?

  1. Ball A, because it was mentioned first and therefore has more energy.
  2. Ball B, because only speed matters for kinetic energy and it is the fastest mentioned relative to A.
  3. Ball C, because it has both high speed and greater mass than the others at that speed.

C.

Ball C, because it has both high speed and greater mass than the others at that speed.

400

A 10 kg rock is held 1 m above Earth’s surface. Rounding gravitational acceleration to 10 m/s^2, what is the rock’s gravitational potential energy relative to the ground?

  1. 1000 J
  2. 110 J
  3. 100 J

C. 

10 x 1 x 10 = 100

500

Two identical balls roll at different speeds. One ball's speed is doubled compared to the other. How does the faster ball's kinetic energy compare to the slower ball's?

  1. It is twice as large because kinetic energy is directly proportional to speed.
  2. It is half as large because faster motion means less time to store energy.
  3. It is four times as large because kinetic energy depends on the square of speed.

C — With equal mass, kinetic energy scales with the square of speed: . Doubling  makes  four times larger, so kinetic energy becomes four times as large.  

500

Which statement correctly applies the law of conservation of energy to a swinging pendulum that gradually slows and stops?

  1. Kinetic energy increases while potential energy and total energy both decrease to zero simultaneously.
  2. Total energy is conserved, but some mechanical energy is transformed and transferred to the surroundings as sound and thermal energy.
  3. Energy is destroyed inside the pendulum until none remains to move it.

B

Total energy is conserved, but some mechanical energy is transformed and transferred to the surroundings as sound and thermal energy.

500

A lever launcher built from permitted materials must be safe and reusable. Which test method provides the most useful data for evaluating both performance and safety?

  1. Ask users whether it seems fun, without checking the device after use
  2. Judge by a single launch that looks impressive without recording measurements
  3. Run multiple trials measuring launch distance and observing for unstable parts or sharp edges after each trial

C — Multiple trials provide reliable performance data, and post-trial inspections address safety and durability, aligning with constraints (safe, reusable) and criteria (performance). A single impressive launch lacks data. Only asking about fun omits safety and performance evidence. Testing once to avoid wear defeats evaluating reusability and safety under repeated use.

500

A lamp plugged into an outlet is modeled as a system. Which statement best describes the energy flows?

  1. Electrical energy enters as an input; light energy and thermal energy leave as outputs.
  2. Light energy enters as an input; electrical energy leaves as an output into the wall.
  3. Chemical energy enters from the air; gravitational potential energy leaves as heat.

A.

Electrical energy enters as an input; light energy and thermal energy leave as outputs.

500

What is the mass of Ms. Thomas's bowling ball (in pounds)?

10 lbs.

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