Question 9.
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?
Answer:
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.
