Energy! We have both types of energy: Kinetic and Potential

Question 1 1) Newton’s second law of motion states that _________ of an object is in the same direction as the net force on the object. A. acceleration B. momentum C. speed D. velocity

Answer The answer is A. Acceleration can be calculated by dividing the net force in newtons by the mass in kilograms.

Question #2 The unit of force is __________. A. joule B. lux C. newton D. watt

Answer! The answer is C. One newton = 1 kg · m/s 2

Question #3 Which is NOT one of the four basic forces? A. gravity B. net C. strong nuclear D. weak nuclear

Answer! The answer is B. The fourth basic force is the electromagnetic force, which causes electricity, magnetism, and chemical interactions between atoms and molecules.

Question #4 According to Newton’s third law of motion, what happens when one object exerts a force on a second object?

Answer! According to Newton’s law, the second object exerts a force on the first that is equal in strength and opposite in direction.

What is energy? Energy is the ability to do work. When something is able to change its environment or itself, it has energy. Energy is the ability to cause change.

Forms of energy: There are many different forms of energy. Sound Light Chemical Mechanical Nuclear Thermal Etc…

Is all energy the same? Is the chemical energy stored in food the same as the energy that comes from the Sun or the energy stored in gasoline? Radiant energy from the Sun travels a vast distance through space to Earth, warming the planet and providing energy that enables green plants to grow.

Energy is transformed but not Changed. Energy from the Sun that warms you and energy from the food that you eat are only different forms of the same thing. It’s form can be changed It can be stored. It can never be destroyed or created.

SI Unit The SI unit of energy is the Joule: It is the same joule we use to measure work!

Kinetic energy An object in motion does have energy. Kinetic energy is the energy a moving object has because of its motion.

Potential Energy Even motionless objects can have energy. This energy is stored in the object. -A hanging (or simply elevated) apple has stored energy.

Conversion If it falls, that stored energy of position is converted to energy of motion. As the apple accelerates, the potential energy is slowly transformed into kinetic energy.

Gravitational Potential Energy Anything that can fall has stored energy called gravitational potential energy. Gravitational potential energy (GPE) is energy stored by objects due to their position above Earth’s surface.

Calculate it… Gravitational potential energy can be calculated from the following equation. On Earth the acceleration of gravity is 9.8 m/s 2, (or 10 m/s 2 )and has the symbol g. Like all forms of energy, gravitational potential energy is measured in joules.

Changing GPE According to the equation for gravitational potential energy, the GPE of an object can be increased by increasing its height above the ground. If two objects are at the same height, then the object with the larger mass has more gravitational potential energy.

Question 1 Energy is the ability to __________. A. Fall B. Create heat C. Create motion D. Do work

Answer! The answer is D. Energy is the ability to do work and has several different forms.

Question #2 What are four different forms of energy?

Answer! Chemical Electrical Nuclear Thermal Light Magnetic Sound Mechanical

Question #3 The kinetic energy of an object depends on __________. A. the object’s mass and speed B. the object’s mass C. the object’s speed D. the acceleration of the object

Answer! The answer is A. Kinetic energy depends on both the mass and speed of the moving object.