Q5 of 15 Page 14

Solve the following example.

An object takes 5 s to reach the ground from a height of 5 m on a planet. What is the value of g on the planet?

Given;

Time for object to reach ground (t) = 5 s;


Height of object from the ground(s) = 5m;


Acceleration due to gravity (g) =? ;


Since when Object is released from the height of 5m it will be in free fall hence its initial velocity (u) = 0;


Now, By Newton’s second equation of motion



Here u = 0, a = g, t = 5s, s = 5m;


Putting these values in the above equation we get;



⇒ .


⇒ .


⇒ .


Hence acceleration due to gravity on the planet is 0.4m/s2.


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Solve the following example.

The radius of planet A is half the radius of planet B. If the mass of A is MA, what must be the mass of B so that the value of g on B is half that of its value on A?

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Solve the following example.

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