答案找到了, 自己算出来的。。。。 |
送交者: eachus 2013月12月20日07:58:11 于 [世界军事论坛] 发送悄悄话 |
回 答: 有一物理问题请教大家 由 eachus 于 2013-12-20 00:42:09 |
How high can you jump on the Moon?On the moon the acceleration due to gravity is Kinetic energy at take-off = potential energy at peak height = work done. W = m * g * h = 75 * 9.8 * 0.5 = 368 J take-off speed: E = 1/2 m * v ^2 ==> v = (2 * 368 / 75) ^0.5 = 3.13 m/s a = v ^2 / (2 s ) = 3.13 ^2 / (2 * 0.4) = 12.26 m/s^2 this acceleration is net acceleration related to ground, after over come the Gravity g = 9.8. total acceleration = a + g = 12.26 + 9.8 m/s^2 = 22.06 m/s^2 exerted force: F = m * a = 75 * (22.06) = 1654.5 Newton We now move the experiment to the Moon the moon the acceleration due to gravity g = 1.62 m/s^2 exerted force is the same, mass is the same, acceleration on the jump on the jump is the same : F = m * a = 75 * (22.06) = 1654.5 Newton net acceleration related to the moon: a = 22.06 - 1.62 = 20.44 m/s^2 potential energy at peak height = work done. W = m * a * s = 75 * 20.44 * 0.4 P = m * g * h m * a * s = m * g * h h = ( a * s )/ g = (20.44 * 0.4) / 1.62 = 5.04 m if the person is wearing a spacesuit with mass m * a * s = (m + 100) * g * h 75 * (20.44 * 0.4) / (175 * 1.62) = h h = 613.2 / 283.5 = 2.16 m |
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