Energy accounting in open, closed and isolated systems
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
A 2 kg cart rolls from rest down a 3 m high ramp; friction makes 18.8 J of thermal energy. With g = 9.8 m/s², what is its final kinetic energy, Ari?
A 1 kg cart rolls from rest down a 5 m high ramp; friction makes 14 J of thermal energy. With g = 9.8 m/s², what is its final kinetic energy, Bo?
A 0.5 kg cart rolls from rest down a 4 m high ramp; friction makes 4.6 J of thermal energy. With g = 9.8 m/s², what is its final kinetic energy, Esme?
A drone lifts a box. If the system is the box and Earth, how is the gain in gravitational energy counted, Jun?
- As a store inside the system
- As work done by gravity from outside
- It isn't counted
A cart slides to a stop on a floor. For which system is the total energy unchanged, Luz?
- The floor alone
- The cart, the floor and the air together
- The cart alone
Read this first
Use this
Energy bar chart (example data), one bar per energy store, height in J. Before: chemical 500 J. After: chemical 450 J. A dashed system boundary surrounds a battery and a fan motor. Two arrows cross it outward: moving air 30 J and heat to the room 20 J.
In the energy bar chart, how much does the battery's chemical store fall, Noah?
- 50 J, matching the energy that leaves
- 30 J, just the moving air
- 450 J
In the energy bar chart, what kind of system is the battery and motor, Pia?
- Closed: energy crosses but matter does not
- Open: matter and energy cross
- Isolated: nothing crosses
Using the table, how much thermal energy was made in trial 1, Ren?
- 550 J
- 104 J
- 50 J
Using the table, how much kinetic energy did the cart gain in trial 2, Tala?
Use the picture in question 8.
- 184 J
- 576 J
- 24 J
Using the table, how much gravitational energy did the cart gain in trial 3, Zee?
Use the picture in question 8.
- 196 J
- 604 J
- 204 J