在地球表面的一個(gè)平臺(tái)上有一臺(tái)秤,秤上站著一人,平臺(tái)由一機(jī)器支撐,可以上下做不同的水平加速運(yùn)動(dòng).當(dāng)臺(tái)秤讀數(shù)的是此人體重的兩倍時(shí),平臺(tái)的加速度是多少?
A.約9.8m/s^2,向上
B.約9.8m/s^2,向下
C.約19.6m/s^2,向上
D.約19.6m/s^2,向下
E.不知道人的質(zhì)量無(wú)法求解.
F(臺(tái)秤給人的支撐力)-W(人的重力) = ma
Let F - W = mg
So,mg = ma,a = g (upward)
Ans :(A)
英語(yǔ)翻譯
英語(yǔ)翻譯
A person is standing on a scale that is located on a platform at the surface of the earh.The platform is supported by a machine that can move the platform up and down at various accelerations while keeping it level.If the person's weight has apparently doubled according to the reading on the scale,what is the acceleration of the platform?
A.about 9.8 m/s^2 up
B.about 9.8 m/s^2 down
C.about 19.6 m/s^2 up
D.about 19.6 m/s^2 down
E.It cannot be determined without knowing the mass of the person.
A person is standing on a scale that is located on a platform at the surface of the earh.The platform is supported by a machine that can move the platform up and down at various accelerations while keeping it level.If the person's weight has apparently doubled according to the reading on the scale,what is the acceleration of the platform?
A.about 9.8 m/s^2 up
B.about 9.8 m/s^2 down
C.about 19.6 m/s^2 up
D.about 19.6 m/s^2 down
E.It cannot be determined without knowing the mass of the person.
英語(yǔ)人氣：590 ℃時(shí)間：2020-06-16 18:33:43
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