What is energy?
Energy is defined as the ability to do work. Work is a force acting over a distance, so energy is the ability to exert forces on different things. For example, pushing a box across a floor takes a certain amount of energy. The amount of energy necessary would depend on the mass of the box, the distance the box is being pushed and the type of surface that the box is being pushed on. Energy can take many different forms. Examples of different types of energy are mechanical energy, electrical energy, thermal (heat) energy, and sound energy.
What are the types of energy?
There are two major types of energy: potential and kinetic energy.
What is kinetic energy?
Kinetic energy is energy due to the motion of an object. Any moving object has kinetic energy and can do work on another object. The larger the mass of an object that's in motion, the greater the kinetic energy of that moving object. The faster the mass is moving, the greater the amount of kinetic energy associated with that moving object.
How is kinetic energy measured?
The metric unit of energy is called the joule, abbreviated as "J."
What is a joule?
One joule is defined as 1 newton times 1 meter or 1 kilogram times (1 meter squared divided by 1 second squared).
What is mass?
Mass is the amount of matter in an object or substance. The mass of an object does not change depending on its location.
How is mass measured?
The metric unit for measuring mass is the gram. The SI unit for measuring mass is the kilogram. Any metric prefix attached to the base gram unit is appropriate for measuring the mass of an object or substance. For instance, mg, cg, or ng.
What is speed?
Speed is defined as the distance an object travels in an elapsed time. A car that travels 50 miles in 2 hours would have a speed of 25 miles per hour.
How is speed measured?
Several different units are used to measure speed. Some of these include miles per hour (mph) kilometers per hour (kph), and meters per second (m/s).
What is acceleration?
Acceleration is the rate of change of velocity over time. Simply put, it is the rate at which an object speeds up or slows down. For example, if a car is standing still and the driver speeds up to 60 miles per hour (mph), the acceleration rate is how quickly the car reached 60 mph. Acceleration also works in the reverse, which is often referred to as deceleration. If the car slows to 20 mph, the deceleration rate is how long it takes the car to slow down. Note that this is different than speed, which is how quickly an object moves over a particular distance.
What is gravity?
Gravity is an attractive force that pulls objects toward the center of Earth or a force by one object that attracts other objects. Newton's law of universal gravitation states that every particle attracts every other particle in the universe with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers.
What is gravitational acceleration?
The gravitational acceleration of an object is the rate at which the object accelerates due to the mass of another object. On Earth's surface in the absence of air, all objects accelerate at about 9.8 m/s2 (meters per second squared) due to the large mass of Earth. An object dropped on the moon's surface would accelerate at a lower rate due to the moon's smaller mass and smaller gravitational force.
Have you ever seen a professional skateboarder do all sorts of tricks on a skateboard ramp? Their tricks involve lots of physics and the transfer and transformation of energy. But what factors affect the energy changes? Get started now investigating the energy changes associated with skateboarding.
