 The sun’s energy is created by nuclear fusion  Energy from the sun travels to earth in the form of ultraviolet radiation.

Energy CAN be transferred, but these transfers do NOT change the total amount of energy

KE= ½ mv 2 Notice that velocity is squared. This means that the velocity of an object has the greatest impact on its kinetic energy!

 Gravitational PE: energy of position (the greater the force of gravity between 2 objects the greater the gravitational potential energy)  Electric PE: energy due to the separation of charges  Chemical PE: energy stored in the bonds of substances

If 100 joules of energy are put into a rollercoaster car to move it to the top of the first hill then the total mechanical energy of the system is equal to 100 joules. PE=100 j KE= 0 j PE= 0 j KE=100 j PE= 50 j KE=50 j

PE= 10j KE= 0j PE= 0j KE= 10j PE= 5j KE= 5j PE= 10j KE= 0j PE= 5j KE= 5j

Which best describes the energy change as the pendulum moves from position 1 to position 2? a. The total energy is decreasing b. The kinetic energy is increasing c. The thermal energy is decreasing d. The potential energy is increasing Energy can neither be created nor destroyed! SO, the total energy CAN NOT CHANGE!

 The faster the particles are moving, the hotter the substance. Solid Liquid Gas

 Temperature is essentially a heat measurement.  Therefore, it is a measure of the AVERAGE kinetic energy rather than the TOTAL kinetic energy  The SI unit of temperature is Kelvin (K)

 Convection: heat transfer by actual movement of matter  Conduction: heat transfer by direct contact of particles  Radiation: transfer of energy that does not require matter

What is the ultimate source of energy on earth? The Sun Energy of motion is called: Kinetic Energy What factor has the largest impact on Kinetic Energy?Velocity Energy that is stored in some manner is called: Potential Energy The sum of the kinetic energy of the particles in a substance:Heat The average kinetic energy of the particles in a substance:Temperature Temperature is measured in ______K The faster the particles in a substance are moving _______ the temperature of the substance greater

 Velocity = distance/ time  SI Unit: m/s  A vector quantity: has magnitude and direction

Distance (m) Time (s) A B C A: Distance is increasing uniformly over time. Therefore, velocity is constant. B: Distance is remaining constant. Therefore, there is not motion during this time interval. C: Distance is decreasing uniformly over time. Therefore, the object is moving back towards its original point with a constant velocity Is the velocity greater at A or C? A : the slope is greater so more distance is covered in a shorter time!

 Acceleration = change in velocity/ time  SI Unit: m/s 2  Vector Quantity: shows both magnitude and direction

A: Velocity is constant. Acceleration is ZERO B: Velocity is increasing uniformly. Acceleration is constant C: Velocity constant at 30 m/s. Acceleration is ZERO D: Velocity is decreasing uniformly. acceleration is constant & negative Velocity (m/s) Time (s)

Distance (m) Time (s)

What would you rather drag across the room?  The refrigerator?  The toaster? What would you rather stand in front of?  An SUV speeding down the highway?  A toy SUV speeding down the table? Think about the difference in damage done by:  A bullet shot from a gun  A bulletthat is thrown

What has more inertia: 1. A 100 kg person running 10 m/s or a 50 kg person running 10 m/s? A 100 kg person has more inertia 2. A jet plane sitting on the runway or a baggage cart sitting on the runway? A jet plane sitting on the runway

 If balanced forces act on an object it does not change its motion.  This does NOT mean that the object is at rest!  It simply means that the object continues at the same velocity. 100 N 10 m/s 0 m/s 100 N

 If an unbalanced force acts on an object it will accelerate in the direction of the greater force. 100 N50 N Accelerating to the left Accelerating downward 25 N 100 N

 Gravity increases as mass increases or distance decreases.  Gravity causes falling objects to accelerate downward.

The Sun has a large mass but it a large distance away from earth The Earth has a small mass compared to the sun, but a large mass compared to a person. Because we are very close to Earth’s surface the Earth’s gravity is greater than the Sun’s. SO, we are attracted to Earth’s surface instead of the Sun’s!

 Air resistance increases as surface area increases.  Air resistance is a form of friction. Gravity Air Resistance: If the skydivers open their parachute they will increase their surface area which increases air resistance and slows their downward decent.

Your weight depends on your location:  The greater the force of gravity the larger your weight Your MASS remains the same Regardless of your location! F weight

 If we could totally eliminate friction:  An object in motion would stay in motion until acted on by an unbalanced force

Work = Force x Distance  The greater the force the greater the work.  The greater distance the object moves the greater the amount of work done.

 Power can also be defined as the rate of energy transfer  The faster energy is transferred or the faster work is done the more power is generated