A 20 kg object falls from a height of 30 meters. How many joules of kinetic energy will the object have just before it hits the ground?
PE= m g h mass in kg, g in m/s^2, h in meters.
30
To calculate the amount of kinetic energy an object has just before it hits the ground, we need to use the formula for kinetic energy:
Kinetic Energy (KE) = 0.5 * mass * velocity^2
In this case, we don't have the velocity directly, but we can find it using the concept of conservation of energy.
First, we need to find the potential energy (PE) when the object is at a height of 30 meters. The formula for potential energy is given by:
Potential Energy (PE) = mass * acceleration due to gravity * height
Acceleration due to gravity is approximately 9.8 m/s^2.
PE = 20 kg * 9.8 m/s^2 * 30 m
= 5880 J
The potential energy will be converted entirely into kinetic energy just before the object hits the ground. Therefore, at that moment, the object's potential energy is equal to its kinetic energy.
KE = PE
= 5880 J
So, the object will have 5880 joules of kinetic energy just before it hits the ground.