A 5 kg object is dropped from a height of 20 m. What is its velocity just before

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Question: A 5 kg object is dropped from a height of 20 m. What is its velocity just before it hits the ground? (Take g = 10 m/s²)

Options:

Correct Answer: 20 m/s

Solution:

Using the formula v² = u² + 2gh, where u = 0, we have v = √(0 + 2*10*20) = √400 = 20 m/s.

A 5 kg object is dropped from a height of 20 m. What is its velocity just before it hits the ground? (Take g = 10 m/s²)

A 5 kg object is dropped from a height of 20 m. What is its velocity just before it hits the ground? (Take g = 10 m/s²)

Step 1: Identify the initial velocity (u) of the object. Since the object is dropped, u = 0 m/s.
Step 2: Identify the height (h) from which the object is dropped. Here, h = 20 m.
Step 3: Identify the acceleration due to gravity (g). We are given g = 10 m/s².
Step 4: Use the formula v² = u² + 2gh to find the final velocity (v) just before the object hits the ground.
Step 5: Substitute the values into the formula: v² = 0² + 2 * 10 * 20.
Step 6: Calculate the right side: v² = 0 + 400, so v² = 400.
Step 7: Take the square root of both sides to find v: v = √400.
Step 8: Calculate the square root: v = 20 m/s.

Kinematics – The question tests the understanding of kinematic equations, specifically the relationship between initial velocity, final velocity, acceleration due to gravity, and displacement.
Free Fall – It assesses knowledge of free fall motion under the influence of gravity, where the only force acting on the object is gravitational force.