If a 2 kg object is dropped from a height, what is its velocity just before hitt

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Question: If a 2 kg object is dropped from a height, what is its velocity just before hitting the ground? (g = 9.8 m/s², h = 20 m) (2023)

Options:

Correct Answer: 19.6 m/s

Solution:

Using v² = u² + 2gh, where u = 0, we find v = √(2 * 9.8 * 20) = 19.6 m/s.

If a 2 kg object is dropped from a height, what is its velocity just before hitting the ground? (g = 9.8 m/s², h = 20 m) (2023)

If a 2 kg object is dropped from a height, what is its velocity just before hitting the ground? (g = 9.8 m/s², h = 20 m) (2023)

Step 1: Identify the variables. We have the height (h) = 20 m and the acceleration due to gravity (g) = 9.8 m/s². The initial velocity (u) is 0 m/s because the object is dropped.
Step 2: Write down the formula to find the final velocity (v) just before hitting the ground. The formula is v² = u² + 2gh.
Step 3: Substitute the known values into the formula. Since u = 0, the equation simplifies to v² = 0 + 2 * 9.8 * 20.
Step 4: Calculate the right side of the equation. First, calculate 2 * 9.8 = 19.6, then multiply by 20 to get 19.6 * 20 = 392.
Step 5: Now we have v² = 392. To find v, take the square root of 392. So, v = √392.
Step 6: Calculate the square root of 392. This gives us v ≈ 19.8 m/s.
Step 7: Conclude that the velocity of the object just before hitting the ground is approximately 19.8 m/s.

Kinematics – The question tests the understanding of kinematic equations, specifically the relationship between velocity, acceleration due to gravity, and height.
Free Fall – It assesses knowledge of free fall motion, where an object is subject only to gravitational acceleration.