A 2 kg ball is dropped from a height of 10 m. What is its speed just before it h
Practice Questions
Q1
A 2 kg ball is dropped from a height of 10 m. What is its speed just before it hits the ground? (2022)
14 m/s
10 m/s
20 m/s
15 m/s
Questions & Step-by-Step Solutions
A 2 kg ball is dropped from a height of 10 m. What is its speed just before it hits the ground? (2022)
Correct Answer: 14 m/s
Step 1: Identify the mass of the ball, which is 2 kg. This information is not needed for the calculation of speed but is part of the problem.
Step 2: Identify the height from which the ball is dropped, which is 10 meters.
Step 3: Recognize that we can use the formula for speed just before hitting the ground, which is derived from energy conservation: v = sqrt(2gh).
Step 4: Identify the acceleration due to gravity (g), which is approximately 9.8 m/s².
Step 5: Plug the values into the formula: v = sqrt(2 * 9.8 m/s² * 10 m).
Step 6: Calculate the value inside the square root: 2 * 9.8 * 10 = 196.
Step 7: Take the square root of 196 to find the speed: sqrt(196) = 14 m/s.
Step 8: Conclude that the speed of the ball just before it hits the ground is 14 m/s.
Energy Conservation – The principle that the total mechanical energy (potential + kinetic) in a closed system remains constant if only conservative forces are acting.
Kinematics – The study of motion without considering the forces that cause it, particularly the equations relating distance, speed, and acceleration.
