Energy, Work And Power Continued
Muhtasari
Two cranes can lift the same load to the same height, yet one finishes in seconds and the other takes a minute. They do the same work but the fast one has more power. Power is the rate of doing work, and it is what separates a sprinter from a stroller and a sports car from a scooter.
In this short but important lesson you will define power precisely, learn its two equivalent equations, and calculate it from work done or energy transferred over time. Every answer here is a number with the unit watt, so getting the substitution and units right is the whole game.
Malengo
- [Core] Understand that mechanical or electrical work done is equal to the energy transferred
- [Core] Recall and use the equation for mechanical working W = Fd = ΔE
- [Core] Describe how useful energy may be obtained, or electrical power generated, from: (a) fossil fuels (b) biofuels (c) water, including waves, tides, and hydroelectric dams (d) geothermal resources (e) nuclear fission (f) light from the Sun (solar cells) (g) infrared and other electromagnetic waves from the Sun to heat water (solar thermal collectors) (h) wind (wind turbines) including references to a boiler, turbine and generator where they are used
- [Core] Understand, qualitatively, the concept of efficiency of energy transfer
- [Supplement] Know that radiation from the Sun is the main source of energy for all our energy resources except geothermal, nuclear and tidal
- [Supplement] Know that energy is released by nuclear fusion in the Sun (detailed knowledge of the process of fusion is not required)
- [Supplement] Know that energy is released by nuclear fission in nuclear reactors (detailed knowledge of the process of fission is not required)
- [Supplement] Define efficiency as: useful energy output (a) efficiency = × 100% total energy input useful power output (b) efficiency = × 100% total power input recall and use the equations
Maelezo ya Somo
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Tathmini ya Somo
Hongera kwa kukamilisha somo la Energy, Work And Power Continued. Sasa kwa kuwa umechunguza dhana na mawazo muhimu, ni wakati wa kuweka ujuzi wako kwa mtihani. Sehemu hii inatoa mazoezi mbalimbali maswali yaliyoundwa ili kuimarisha uelewaji wako na kukusaidia kupima ufahamu wako wa nyenzo.
Utakutana na mchanganyiko wa aina mbalimbali za maswali, ikiwemo maswali ya kuchagua jibu sahihi, maswali ya majibu mafupi, na maswali ya insha. Kila swali limebuniwa kwa umakini ili kupima vipengele tofauti vya maarifa yako na ujuzi wa kufikiri kwa makini.
Tumia sehemu hii ya tathmini kama fursa ya kuimarisha uelewa wako wa mada na kubaini maeneo yoyote ambapo unaweza kuhitaji kusoma zaidi. Usikatishwe tamaa na changamoto zozote utakazokutana nazo; badala yake, zitazame kama fursa za kukua na kuboresha.
- Power is defined as: A. force x distance B. work done per unit time C. energy x time D. force x time Answer: B
- A motor does 4000 J of work in 20 s. Its power is: A. 80 000 W B. 200 W C. 0.005 W D. 4020 W Answer: B
- The unit of power, the watt, is equivalent to: A. 1 joule B. 1 joule per second C. 1 newton metre D. 1 newton per second Answer: B
- A 1500 W heater runs for 60 s. The energy transferred is: A. 25 J B. 1560 J C. 90 000 J D. 1500 J Answer: C
- A crane lifts a 200 N load 5 m in 10 s. The output power is: A. 100 W B. 1000 W C. 10 W D. 4 W Answer: A
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Inapatikana kwenye programu ya Green Bridge
Pakua programu ya Green Bridge CBT kwenye simu yako au kompyuta yako ili kupata maelezo kamili ya masomo, maswali ya mazoezi, na mengi zaidi.
Vitabu Vinavyopendekezwa
Fanya Mazoezi ya Maswali ya Majaribio
Ungependa kufanya mazoezi ya maswali ya majaribio kuhusu Energy, Work And Power Continued? Pakua programu ya Green Bridge CBT ili kupata maswali ya majaribio na tathmini kamili za mazoezi kuhusu mada hii.
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