Answer :
Final Answer:
The rock will be 5 m from the ground level at 2.31 s.
The correct answer is option b) 2.31 s
Explanation:
To determine the time it takes for the rock to reach 5 meters from the ground level, we need to analyze the situation using the concept of motion under constant acceleration. In this case, the rock experiences a constant acceleration due to gravity, which is approximately 9.81 m/s².
First, let's establish the initial conditions. We know that the rock starts at the ground level (0 m) and we want to find the time when it reaches 5 m above the ground. Therefore, the change in height (Δh) is 5 m.
Now, we can use the equation for motion under constant acceleration, which is:
Δh = h + 0.5 * a * t²
Where Δh is the change in height, h is the final height, a is the acceleration, and t is the time taken to reach the final height.
We need to find the value of t. Rearranging the equation to solve for t, we get:
t = sqrt(2 * (Δh - h) / a)
Plugging in the values, we have:
t = sqrt(2 * (5 - 0) / 9.81)
t = sqrt(10 / 9.81)
t ≈ 2.31 s
So, the rock will be 5 m from the ground level at approximately 2.31 seconds.
Therefore, the correct answer is option b) 2.31 s
