A pendulum of length 2 m swings from a height of 1 m. What is the speed at the l
Practice Questions
Q1
A pendulum of length 2 m swings from a height of 1 m. What is the speed at the lowest point of the swing? (g = 9.8 m/s²)
4.4 m/s
3.1 m/s
2.8 m/s
5.0 m/s
Questions & Step-by-Step Solutions
A pendulum of length 2 m swings from a height of 1 m. What is the speed at the lowest point of the swing? (g = 9.8 m/s²)
Step 1: Identify the height from which the pendulum swings. In this case, it is 1 meter.
Step 2: Identify the length of the pendulum, which is 2 meters. This is not directly needed for the calculation but helps understand the setup.
Step 3: Use the formula for gravitational potential energy (PE) at the height: PE = mgh, where m is mass, g is the acceleration due to gravity (9.8 m/s²), and h is the height (1 m).
Step 4: At the lowest point of the swing, all potential energy is converted into kinetic energy (KE). The formula for kinetic energy is KE = 0.5mv².
Step 5: Set the potential energy equal to the kinetic energy: mgh = 0.5mv². The mass (m) cancels out from both sides of the equation.
Step 6: Rearrange the equation to solve for v (speed): gh = 0.5v².
Step 7: Multiply both sides by 2 to eliminate the 0.5: 2gh = v².
Step 8: Take the square root of both sides to find v: v = sqrt(2gh).
Step 9: Substitute the values for g (9.8 m/s²) and h (1 m) into the equation: v = sqrt(2 * 9.8 * 1).
Step 10: Calculate the value: v = sqrt(19.6) which is approximately 4.4 m/s.
Conservation of Energy – The principle that energy cannot be created or destroyed, only transformed from one form to another, in this case from potential energy to kinetic energy.
Potential Energy – The energy stored in an object due to its height above the ground, calculated as mgh.
Kinetic Energy – The energy of an object in motion, calculated as 0.5mv².
Pendulum Motion – The motion of a pendulum involves converting potential energy at its highest point to kinetic energy at its lowest point.