Energy accounting in open, closed and isolated systems

Grade 11 Science Worksheet - Challenge Me

NameDate

Circle the best answer, or write your answer on the line.

A motor does 500 J of work on a cart-and-ramp system. The cart gains 294 J of gravitational and 120 J of kinetic energy. How much thermal energy is made, Ari?
A motor does 300 J of work on a cart-and-ramp system. The cart gains 147 J of gravitational and 60 J of kinetic energy. How much thermal energy is made, Bo?
A motor does 800 J of work on a cart-and-ramp system. The cart gains 392 J of gravitational and 250 J of kinetic energy. How much thermal energy is made, Esme?
4.
An electric kettle with no lid takes in 300 kJ. The water gains 250 kJ of thermal energy and 30 kJ leaves with the steam. Where are the other 20 kJ, Jun?
- Warming the kettle and the room air
- Destroyed in the heater
- Stored as gravitational energy in the steam
5.
Why is a kettle with no lid an open system, Kira?
- Its water stays inside the kettle
- Steam, which is matter, leaves it
- No energy can cross its boundary
6.
What change would make a lidless kettle a closed system, Luz?
- Thick insulation, with the top still open
- A bigger heater
- A tight lid, so no steam escapes
7.
Milo says friction destroys energy when a box slides to a stop. Agree or disagree?
- Disagree: it becomes thermal energy
- Agree: the box ends with less energy, so energy was lost from the world
- Agree: the kinetic energy is gone for good
8.
Noah says the total energy of an isolated system stays the same, even with friction inside it. Agree or disagree?
- Disagree: friction uses energy up
- Disagree: isolated systems leak heat
- Agree: friction moves energy between stores
9.
Pia says a closed system's total energy can change. Agree or disagree?
- Agree: energy can cross its boundary
- Disagree: closed means nothing crosses
- Disagree: its matter stays the same, so its energy does too
10.
A drone's battery gives out 900 J while it lifts a 2 kg box 30 m at a steady speed. With g = 9.8 m/s², how much goes to heat and moving air, Ren?
- 1488 J
- 312 J
- 588 J

Energy accounting in open, closed and isolated systems

Answer Key - Grade 11 Science Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

A motor does 500 J of work on a cart-and-ramp system. The cart gains 294 J of gravitational and 120 J of kinetic energy. How much thermal energy is made, Ari?
86 J
A motor does 300 J of work on a cart-and-ramp system. The cart gains 147 J of gravitational and 60 J of kinetic energy. How much thermal energy is made, Bo?
93 J
A motor does 800 J of work on a cart-and-ramp system. The cart gains 392 J of gravitational and 250 J of kinetic energy. How much thermal energy is made, Esme?
158 J
4.
An electric kettle with no lid takes in 300 kJ. The water gains 250 kJ of thermal energy and 30 kJ leaves with the steam. Where are the other 20 kJ, Jun?
- Warming the kettle and the room air
- Destroyed in the heater
- Stored as gravitational energy in the steam
5.
Why is a kettle with no lid an open system, Kira?
- Its water stays inside the kettle
- Steam, which is matter, leaves it
- No energy can cross its boundary
6.
What change would make a lidless kettle a closed system, Luz?
- Thick insulation, with the top still open
- A bigger heater
- A tight lid, so no steam escapes
7.
Milo says friction destroys energy when a box slides to a stop. Agree or disagree?
- Disagree: it becomes thermal energy
- Agree: the box ends with less energy, so energy was lost from the world
- Agree: the kinetic energy is gone for good
8.
Noah says the total energy of an isolated system stays the same, even with friction inside it. Agree or disagree?
- Disagree: friction uses energy up
- Disagree: isolated systems leak heat
- Agree: friction moves energy between stores
9.
Pia says a closed system's total energy can change. Agree or disagree?
- Agree: energy can cross its boundary
- Disagree: closed means nothing crosses
- Disagree: its matter stays the same, so its energy does too
10.
A drone's battery gives out 900 J while it lifts a 2 kg box 30 m at a steady speed. With g = 9.8 m/s², how much goes to heat and moving air, Ren?
- 1488 J
- 312 J
- 588 J