Answer:
The answer is below
Explanation:
Using the equation of newton law of motion for an object thrown vertially upwards:
v = u - gt
where u is the initial velocity, g = acceleration due to gravity and t is the time taken to reach maximum height.
Given that u = 30 m/s, at maximum height, v = 0, g = 10 m/s². Therefore:
0 == 30 - 10t
10t = 30
t = 30/10
t = 3 seconds
b) The time taken to reach the highest point = 3 seconds. Therefore the total time before it returns back to its original height = 2t = 2(3) = 6 seconds