A 2 kg object is dropped from a height of 20 m. What is its speed just before it

A 2 kg object is dropped from a height of 20 m. What is its speed just before it hits the ground? (Assume g = 10 m/s²)

A 2 kg object is dropped from a height of 20 m. What is its speed just before it hits the ground? (Assume g = 10 m/s²)

Step 1: Identify the mass of the object. The mass (m) is 2 kg.
Step 2: Identify the height from which the object is dropped. The height (h) is 20 m.
Step 3: Identify the acceleration due to gravity. The value of g is 10 m/s².
Step 4: Use the formula for potential energy (PE) at height: PE = mgh.
Step 5: Calculate the potential energy: PE = 2 kg × 10 m/s² × 20 m = 400 J.
Step 6: Understand that just before hitting the ground, all potential energy converts to kinetic energy (KE).
Step 7: Use the formula for kinetic energy: KE = 0.5 mv².
Step 8: Set the potential energy equal to kinetic energy: 400 J = 0.5 × 2 kg × v².
Step 9: Simplify the equation: 400 J = 1 kg × v².
Step 10: Solve for v²: v² = 400 J / 1 kg = 400.
Step 11: Take the square root to find v: v = √400 = 20 m/s.

Conservation of Energy – The principle that the total energy in a closed system remains constant, allowing potential energy to convert into kinetic energy.
Kinematic Equations – Equations that describe the motion of objects under constant acceleration, which can also be used to find final velocity.
Gravitational Potential Energy – The energy an object possesses due to its height above the ground, calculated as mgh.
Kinetic Energy – The energy of an object in motion, calculated as 0.5 mv².