InterviewSolution
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29. The acceleration due to gravity g on earth is 9.8ms?. What would the value of g for a planetwhose size is the same as that of earth but thedensity in twice that of earth?(a) 19.6 ms 2(c) 4.9 ms(b) 9.8 ms(d) 2.45 ms2 |
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Answer» size of planet is same as that of earth, it means volume of planet is same as volume of earth. So, the radius of planet = radius of earth = R {let } Also we know, density = mass/volume , If volume is constant then density depends upon mass and it is directly proportional to mass. A/C to question, density of planet is twice that of earth. ∴mass of planet is twice that of earth.Let mass of earth is M Then mass of planet is 2M Now, g = GM/R² , for earth g' = G(2M)/R² , for planet .Here you observed , 2g = g' Hence, acceleration due to gravity on surface of planet is two times of acceleration due to gravity on Earth's surface.E.g., acceleration due to gravity on planet' surface = 2 × 9.8 = 19.6 m/s² |
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