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Physics in Context · Part 2 of 2
6 exam-style questions with model answers, plus 7 quick multi-choice questions — every question on this part of the standard, grouped by the 2 pages of notes they come from.
Write a full answer before you reveal the model one. That comparison is where the learning happens.
In the context of sports equipment, a tennis racquet is strung with strings under tension. State the physics concept most relevant to describing how the strings behave when hit by a ball.
Explain why a longer bungee cord, rather than a shorter one of the same material, is chosen for a heavier jumper, using the concept of Hooke's Law.
Discuss, with a supporting calculation, why regenerative braking in an electric vehicle is more energy-efficient than conventional friction braking, in terms of energy transformation.
In the context of a hydroelectric power station, describe the energy transformations that occur from the water stored in the lake to the electricity leaving the station.
A hydro station has a head of m and passes kg of water per second through its turbines at an efficiency of .
Calculate the electrical power output, and explain why the station's output falls when the lake level drops. Take N kg−1.
Discuss why a hydroelectric station achieves a much higher efficiency than a coal-fired station, and use this physics to evaluate the claim that "a hydro lake is a battery". Link at least two concepts.