Content

• To step
• Part 1 of 3: Understanding kinetic energy
• Part 2 of 3: Calculating kinetic energy
• Part 3 of 3: Using kinetic energy to determine vector velocity or mass

There are two forms of energy: potential and kinetic energy. Potential energy is the energy of an object relative to the position of another object. For example, if you are on top of a hill, you have more potential energy than at the bottom of the hill. Kinetic energy is the energy of an object in motion. Kinetic energy can be generated by vibration, rotation or translation (displacement). The kinetic energy of any object can be easily determined using an equation that considers the object's mass and speed.

To step

Part 1 of 3: Understanding kinetic energy

1. Know the formula for calculating kinetic energy. The formula to calculate the kinetic energy (KE) is KE = 0.5 x pl. Here is m the mass (how much matter is present in an object) and v stands for the (vector) speed of the object (or the degree to which an object moves).
   • The answer should always be stated in joules (J), the standard unit of measurement for kinetic energy. It is equivalent to 1 kg * m / s.
2. Determine the mass of an object. If you solve a problem where the mass is not given, then you will have to determine it yourself. You can do this by weighing the object on a balance where the mass in kilograms (kg) is obtained.
   • Adjust the balance. Before you weigh the object, you will have to set the balance to zero. Zeroing the scale is called calibration.
   • Place the object on the scale. Carefully place the object on the scale and record its mass in kilograms.
   • Convert the number of grams to kilograms if necessary. For the final calculation, the mass should be in kilograms.
3. Calculate the speed of the object. Often the speed of the object is given in a statement. If not, you can determine the speed using the distance an object is moving and the time it takes to travel that distance. The vector speed unit is meters per second (m / s).
   • Vector speed is defined by the equation of displacement divided by time: v = d / t. Vector speed is a vector, which means that it has both a magnitude and a direction. The magnitude is a numerical value for indicating the speed, while direction is the direction of the speed during the movement.
   • For example, the vector speed of an object can be 80 m / s or -80 m / s, depending on the direction in which the object is moving.
   • To calculate the vector speed, you divide the distance traveled by the object by the time it takes to cover that distance.

Part 2 of 3: Calculating kinetic energy

1. Write down the equation. The formula for calculating kinetic energy (KE) is KE = 0.5 x pl. This states m for mass (the amount of matter in an object), and v represents the vector velocity of an object (the displacement of an object).
   • Your answer should always be given in joules (J), a standard measure of kinetic energy measurement. It is equivalent to 1 kg * m / s.
2. Apply the mass and vector velocity to the equation. If you don't know the mass or vector velocity of the object, you will have to calculate this. But suppose you know both values ​​and want to solve the following problem: Determine the kinetic energy of a 55 kg woman running at a speed of 3.87 m / s. Since you know the woman's mass and speed, you can enter it into the equation:
   • KE = 0.5 x pl
   • KE = 0.5 x 55 x (3.87)
3. Solve the equation. If you have entered the mass and vector velocity into the equation, you can solve for the kinetic energy (KE). Square the speed and then multiply all the variables together. Do not forget to give your answer in joule (J).
   • KE = 0.5 x 55 x (3.87)
   • KE = 0.5 x 55 x 14.97
   • KE = 411.675 J

Part 3 of 3: Using kinetic energy to determine vector velocity or mass

1. Write down the equation. The formula for calculating kinetic energy (KE) is KE = 0.5 x pl. This states m for mass (the amount of matter in an object), and v represents the vector velocity of an object (the displacement of an object).
   • Your answer should always be given in joules (J), the standard measure of kinetic energy measurement. It is equivalent to 1 kg * m / s.
2. Enter the variables you know. For some exercises the kinetic energy and mass, or the kinetic energy and vector velocity, may be known. The first step in solving this problem is to enter all the variables that are known.
   • Example 1: What is the speed of an object with a mass of 30 kg and a kinetic energy of 500 J?
     • KE = 0.5 x pl
     • 500 J = 0.5 x 30 x v
   • Example 2: What is the mass of an object with a kinetic energy of 100 J and a speed of 5 m / s?
     • KE = 0.5 x pl
     • 100 J = 0.5 x m x 5
3. Rearrange the equation to solve for the unknown variable. You can find out the unknown variable using algebra, by shifting all known variables to one side of the equation.
   • Example 1: What is the speed of an object with a mass of 30 kg and a kinetic energy of 500 J?
     • KE = 0.5 x pl
     • 500 J = 0.5 x 30 x v
     • Multiply the mass by 0.5: 0.5 x 30 = 15
     • Divide the kinetic energy by the product: 500/15 = 33.33
     • Calculate the square root to find the speed: 5.77 m / s
   • Example 2: What is the mass of an object with a kinetic energy of 100 J and a speed of 5 m / s?
     • KE = 0.5 x pl
     • 100 J = 0.5 x m x 5
     • Square the speed: 5 = 25
     • Multiply by 0.5: 0.5 x 25 = 12.5
     • Divide the kinetic energy by the product: 100 / 12.5 = 8 kg