题干

某地已兴建3座抽水蓄能水电站,它可调节电力供应.深夜时,用过剩的电能通过水泵把下蓄水池的水抽到高处的上蓄水池内,白天则通过闸门放水发电,以补充电能不足.若上蓄水池长为150m,宽为30m,如图所示,从深夜11点至清晨4点抽水,使上蓄水池水面升高20m,而抽水过程中水上升的高度始终保持为40m.已知抽水机的效率为 80%,发电机的效率为60%,g取10N/kg.则白天通过闸门放水发电将夜晚抽水蓄的能转化成电能,给电网补充的电能为____J;则抽水的功率是____W.

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On Friday, April 1, Inner Affair goes back to the days of funk! Classic Tunes from the 70's and 80's by DJs Den & Sion, 9pm till late.

Tickets: Free entrance for those in costume, otherwise 50 yuan (US$6)

Time/Date: 9 pm, April 1

Place: Inner Affair, 1/F Qiankun Dasha, 6 Sanlitun Xiliujie, Chaoyang District

Tel: 8454-0321

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The "worst" party

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Tickets: Free entrance

Time/Date: 9 pm, April 1

Place: Pula Pula, Tianze Lu, Oriental Seven Colours Plaza, Chaoyang District

Tel: 6466-8575

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The evening features three glasses of wine for participants and a special exhibition.

Time/Date: 7 to 10 pm, April 14

Place: Le Rendezvous, 3 Gongti Beilu, across from the Pacific Century Plaza, Chaoyang District

Tel: 6462-9110

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Marco V

Dutch DJ Marco V drops by Banana for a gig which is supported by Hong Kong's DJ Spark.

Marco V has been around for many years, as an inventive, style blending deejay and a successful and devoted producer. His spinning is energetic, crowd pleasing and never sees an empty dance floor. He was ranked No. 15 in this year's international DJ MAG DJ Top100.

Tickets: 40 yuan (US$4.80) in advance, 50 yuan (US$6) at the door, both including a free drink

Time/Date: 10 pm to 4 am, March 31, April 1

Place: Banana, in the lobby of the Scitech Hotel, 22 Jianwai Dajie, Chaoyang District

Tel: 6528-3636