1. Today: Go over Review Packet from last time Reviews 3 and 4 Homework: Review Packet

2. Elastic potential - Potential energy stored as a result of changing the shape of an elastic object, such as the stretching of a spring Thermal – the kinetic energy of moving atoms or molecules in a substance Electric – the kinetic energy of moving electrons Electromagnetic – radiant energy that travels in waves Nuclear – potential energy stored in the forces that hold the protons and neutrons together in the center of an atom. Chemical – potential energy stored in bonds between atoms Translational motion – kinetic energy in an object that is moving from one place to another Rotational motion – kinetic energy of a spinning object Sound – kinetic energy of atoms vibrating in bulk Gravitational potential – energy stored in an object as it moves away from the center of Earth

3. electrical energy to sound energy: radio playing music chemical energy to motion energy: a person running, a battery powered toy moving electromagnetic energy to electrical energy: solar powered device working thermal energy to sound energy: a crackling fire

4. What happens to the particles in a substance as the temperature rises? Temperature is a measure of thermal energy. Thermal energy is the motion of the particles of a substance so if the temperature of a substance is rising that means the particles are moving faster. This causes the particles to collide more often and with more energy so they will get pushed farther apart from each other. As the particles move farther apart, the density of the object decreases. Where does most of the energy on Earth come from? Radiant energy from the sun Trace the energy you got from your breakfast back to the Sun. Bacon  chemical energy in the pig’s food  radiant energy from the sun Trace the electrical energy in our homes back to the Sun. Light bulb  electrical energy in wires  kinetic energy of turbines  kinetic energy of water (river)  kinetic energy of water moving through the water cycle  radiant energy of from the sun

5. Explain the difference between speed and acceleration. Speed is the rate of change of position while acceleration is the rate of change of speed. The speed of an object is how its position changes over time while the acceleration is how its speed changes over time. Speed = d/t so its units are distance per time like m/s Acceleration = change in speed ÷ change in time so its units are speed per unit time like m/s/s How are mass and weight different? Mass is the amount of matter in a substance while weight is the measure of the force of gravity on an object Weight will change if the force of gravity changes but the mass would be the same if you go to the moon, you will weigh less because there will be less gravity but your body hasn’t changed so you still have the same mass

6. What are 3 examples of balanced forces? Sum of all the forces on an object = zero Object is at rest or moving at constant velocity in a straight line What are 3 examples of unbalanced forces? Sum of all the forces on an object ≠ zero Object is accelerating or decelerating or changing direction

7. Explain how is air resistance a type of friction? Friction is a force that opposes motion because the molecules of different substances come in contact with each other As an object moves through the air, it collides with air molecules and this interaction opposes motion therefore it is a type of friction

8. Newton’s Laws of Motion 1 st law: an object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force Example: a ball sitting on the floor or a ball flying through the air (after you release it)

9. 2 nd law: Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object) Kicking a ball is fun, kicking a large rock is not (larger mass requires a larger force to move it)

10. 3 rd law: For every action there is an equal and opposite re-action

11. The normal force is the force exerted on objects that keep the object from falling because of gravity The normal force only acts on objects that are in contact with a surface

12. An apple on a desk A ball rolling down a ramp Pushing a grocery cart (the cart is in motion) FGFG FNFN FGFG FGFG FNFN F F FNFN FAFA

13. It takes you 65 minutes to walk to school. Your home is 3 miles from school. Speed = d/t Speed = 3 mi/65 min Speed = 0.05 mi/min On Monday, it takes your mom 22 minutes to drive to work. On Tuesday it takes 17 minutes. If you live 45 miles from work, how much faster was you mom driving on Monday compared to Tuesday? Speed = d/t Monday Speed = 45 mi/22 min Monday Speed = 2.05 mi/min Tuesday Speed = 45 mi/17 min Tuesday Speed = 2.64 mi/min 2.05 mi/min = 123 mph 2.64 mi/min = 158.4 mph

14. A race car accelerates uniformly from 18.5 m/s to 46.1 m/s in 2.47 seconds. Acceleration = change in speed change in time Acceleration = 27.6 m/s 2.47 s Acceleration = 11.17 m/s/s Rocket-powered sleds are used to test the human response to acceleration. If a rocket-powered sled is accelerated to a speed of 444 m/s in 1.83 seconds what is its acceleration? Acceleration = change in speed change in time Acceleration = 444 m/s 1.83 s Acceleration = 242.62 m/s/s

15. Graph 1 matches description B because the distance is increasing at a steady rate. Graph 2 matches description a because the distance isn’t changing over time. Graph 3 matches description C because the distance is increasing at first but over time, the distance isn’t changing as fast