How is a joule defined
A joule is defined as the amount of energy required to produce one watt of power for one second.
A joule is a unit of energy in the International System of Units (SI). It is defined as the amount of work done when a force of one newton acts upon an object that moves by one meter in the direction of the force. The formula to calculate the amount of energy (in joules) is:
Energy (in joules) = Force (in newtons) × Distance (in meters)
So to measure the energy in joules, you need to know the force applied to an object and the distance it moves in the direction of that force. Let's say, for example, you want to find out how much energy is required to lift a 10-kilogram object to a height of 5 meters.
First, you need to calculate the force required using Newton's second law of motion, which states that force is equal to mass multiplied by acceleration. Since the object is not accelerating, you can use the force due to gravity, which is the mass of the object multiplied by the acceleration due to gravity (9.8 m/s²). In this case, the force required would be:
Force = Mass × Acceleration
Force = 10 kg × 9.8 m/s²
Force = 98 N (newtons)
Now that you have the force, you can calculate the energy required using the formula mentioned earlier:
Energy (in joules) = Force (in newtons) × Distance (in meters)
Energy = 98 N × 5 m
Energy = 490 J (joules)
Therefore, it would take 490 joules of energy to lift a 10-kilogram object to a height of 5 meters, assuming there are no other external factors or energy losses involved.