Unit 4.1 E bar charts 1 key.pdf - Chemistry Unit 4.1: Energy bar ... - Free Printable

Based on the analysis of the three problems presented in the worksheet, here is the solution and explanation for each:

Problem 1: A ball rolling down a ramp

* Initial State: The ball is at rest at the top of the ramp. At this point, it possesses only gravitational potential energy (PEg) due to its height. Its kinetic energy (KE) is zero because it is not moving.
* Final State: As the ball rolls down the ramp, it gains speed. This means it now has kinetic energy (KE). Simultaneously, its height decreases, so its gravitational potential energy (PEg) decreases.
* Energy Transformation: The decrease in gravitational potential energy is converted into an increase in kinetic energy. The total mechanical energy (KE + PEg) remains constant, assuming no friction or air resistance.
* Solution: The "Energy Flow" should show an arrow from PEg to KE. The bar charts correctly reflect this: the initial chart has only a PEg bar, and the final chart has a smaller PEg bar and a new KE bar.

Problem 2: A cart compressing a spring on a frictionless surface

* Initial State: The cart is moving towards the spring with some velocity. It possesses kinetic energy (KE). The spring is uncompressed, so its elastic potential energy (PEe) is zero.
* Final State: As the cart compresses the spring, it slows down. This means its kinetic energy (KE) decreases. The compressed spring stores energy as elastic potential energy (PEe).
* Energy Transformation: The decrease in kinetic energy is converted into an increase in elastic potential energy. The total mechanical energy (KE + PEe) remains constant, assuming a frictionless surface.
* Solution: The "Energy Flow" should show an arrow from KE to PEe. The bar charts correctly reflect this: the initial chart has only a KE bar, and the final chart has a smaller KE bar and a new PEe bar.

Problem 3: A cart going up a frictionless incline

* Initial State: The cart is moving up the incline. It possesses kinetic energy (KE) due to its motion. Its gravitational potential energy (PEg) is low because it is at the bottom of the incline.
* Final State: As the cart moves up the incline, it slows down. This means its kinetic energy (KE) decreases. Simultaneously, its height increases, so its gravitational potential energy (PEg) increases.
* Energy Transformation: The decrease in kinetic energy is converted into an increase in gravitational potential energy. The total mechanical energy (KE + PEg) remains constant, assuming a frictionless incline.
* Solution: The "Energy Flow" should show an arrow from KE to PEg. The bar charts correctly reflect this: the initial chart has a larger KE bar and a small PEg bar, and the final chart has a smaller KE bar and a larger PEg bar.

In summary, all three problems demonstrate the principle of conservation of mechanical energy, where energy is transformed from one form to another without any loss in the idealized, frictionless scenarios depicted.