R /Ω | 0 | 2 | 4 | 6 | 8 | 10 | 12 | 14 | … |
F /N | 5 | 55 | 105 | 155 | 205 | 255 | 305 | 355 | … |
不计杠杆、弹簧、滑片、细绳的重力,不计摩擦,不计弹簧电阻;整套装置始终处于平衡状态,物体A始终不离开地面;灯泡电阻不变,且不会被烧坏。(g=10N/kg)求:
(1)人的拉力最小时,灯泡的实际功率是多少?
(2)当灯泡正常发光时,人对地面的压强是多少?
(3)物体A的质量至少是多少?
同类型试题
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2
y = sin x, x∈R, y∈[–1,1],周期为2π,函数图像以 x = (π/2) + kπ 为对称轴
y = arcsin x, x∈[–1,1], y∈[–π/2,π/2]
sin x = 0 ←→ arcsin x = 0
sin x = 1/2 ←→ arcsin x = π/6
sin x = √2/2 ←→ arcsin x = π/4
sin x = 1 ←→ arcsin x = π/2