A hybrid bus uses a Regenerative Braking System (RBS) to recover and store kinetic energy when the bus slows down. This energy can later be released to assist with acceleration.
The bus approaches a stop and decelerates from 22 m/s to 7.0 m/s in 5.0 s. Calculate the deceleration.
The kinetic energy lost during the braking in (a) is 8.0 × 105 J. 60% of this lost energy is transferred to the storage system. Determine the amount of energy stored.
The bus later uses this stored energy to provide 90 kW of useful extra electrical power for 4.0 s. Calculate the useful energy released.
Calculate the efficiency of the energy storage and recovery system (defined as the ratio of useful energy released to the energy stored).
Suggest a possible device to store energy when a moving vehicle slows down, and state the physical change that occurs in that device as more energy is stored.
533 exam-style questions on CIE IGCSE Physics 1.7 Energy, work and power, covering 1.7.1a Energy stores and energy transfers, 1.7.1b Conservation of energy, 1.7.1c Kinetic and gravitational potential energy, 1.7.2 Work done, 1.7.3 Energy resources, 1.7.3a Energy resources and electricity generation, 1.7.3b Nuclear fusion as an energy source, 1.7.3c Efficiency of energy transfer, and 1.7.4 Power. Each one has a worked solution and a mark scheme showing where the marks go.