(1)距水箱底15cm处的鱼受到的压强P=ρgh=1000kg/m3×10N/kg×(0.55m-0.15m)=4000Pa. 答:距水箱底15cm处的鱼受到的压强是4000Pa. (2)水的质量m=ρV=1000kg/m3×0.9m×0.4m×0.55m=198kg, 水吸收热量Q吸=cm(t-t0)=4.2×103J/(kg•℃)×198kg×(30℃-25℃)=4.158×106J, 消耗电能W===4.62×106J, 因为P=;所以加热时间为t== =11550s. 答:加热时间为11550s. |