A 50 kg object is dropped from a height of 20 m. What is the speed just before i

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Question: A 50 kg object is dropped from a height of 20 m. What is the speed just before it hits the ground? (g = 10 m/s²) (2020)

Options:

Correct Answer: 20 m/s

Exam Year: 2020

Solution:

Using v² = u² + 2gh, v² = 0 + 2 * 10 m/s² * 20 m = 400, v = √400 = 20 m/s.

A 50 kg object is dropped from a height of 20 m. What is the speed just before it hits the ground? (g = 10 m/s²) (2020)

A 50 kg object is dropped from a height of 20 m. What is the speed just before it hits the ground? (g = 10 m/s²) (2020)

Step 1: Identify the initial speed (u) of the object. Since the object is dropped, u = 0 m/s.
Step 2: Identify the acceleration due to gravity (g). Given g = 10 m/s².
Step 3: Identify the height (h) from which the object is dropped. Given h = 20 m.
Step 4: Use the formula v² = u² + 2gh to find the final speed (v) just before hitting the ground.
Step 5: Substitute the values into the formula: v² = 0 + 2 * 10 m/s² * 20 m.
Step 6: Calculate the right side: 2 * 10 * 20 = 400.
Step 7: Now, v² = 400, so take the square root of 400 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, and displacement.
Gravitational Acceleration – It assesses the knowledge of gravitational acceleration and its effect on falling objects.