Newton s Laws Listening Guide. Directions: Complete the Listening Guide by listening and following along with the PowerPoint presentation.

Transcription

1 Name: Period: 8 th Grade Science - Ganey Newton s Laws Listening Guide Directions: Complete the Listening Guide by listening and following along with the PowerPoint presentation. What is a force? A force is an interaction between 2 objects involving a. Forces are vectors - they are drawn as arrows (have size and direction). The units of measure for force is:. Draw an object being pushed with a force vector! Unbalanced and Balanced Forces cause objects to accelerate (like your object being pushed). Balanced forces means. Can you think of an example of when forces are balanced and therefore do NOT cause an object to accelerate? Virtual Forces Lab Force or Action Force Vector Prediction (draw in Force Vectors ) Real-World Example (List an example of each force or action in real-life) Squeezing/Compression Stretching/Tension Bending Sliding/Shearing Twisting/Torsion

2 Newton s First Law Inertia is a. All objects are. They are made of. Stuff you can see or touch! What is an object? Anything made of matter ( ) is an object. Aristotle s View WRONG!!! The Greeks thought there were two types of motion: Natural motion - what an object naturally wants to do Violent motion - what an object has to be forced to do The Greeks did not get the idea of! Galileo s View Realized the role of by rolling marbles down ramps and sliding objects across tables. If left to themselves,. objects keep the! o No Acceleration! Can you think of a situation when there is no friction? Newton s First Law Objects at rest,. o If an object is still, then it will stay still unless you push or pull it. Objects in motion,. o If an object is in motion, then it will stay at that velocity unless you push or pull it. Challenge Question Tablecloth Video Why do the items in the video stay in the same place when the tablecloth is pulled away? Newton s First Law - Law of Inertia Newton s First Law says that objects do not accelerate on their own. This property of matter, which causes objects to, has been named inertia. The of an object the harder to accelerate (boulder vs. rock) So the bigger the mass, then the. Which object has more inertia?

3 Check for Understanding Inertia Activity Pick 5 objects in the room and label them from greatest inertia to least inertia Explain in words what inertia means. Equilibrium If an object is or moving at a it is at (happy). Static Equilibrium Dynamic Equilibrium Draws force vectors on the objects above to show that the forces are balanced in equilibrium. Inertia Demo What do you think will happen to the cart and tennis ball when it gets to the bottom of the ramp? Make a prediction and explain your reasoning. Complete Chapter 1 Reading and answer the section questions 1-3 from page 47 below:

4 Newton s Second Law Force = mass x acceleration Newtons = kilograms x m/s 2 Mass Weight Your Weight on Other Worlds Acceleration due to on the Moon is than on Earth. Gravitational acceleration on Earth = Gravitational acceleration on Moon = So, you would on the Moon than on Earth. But you would have the on both the! You are still you you are still made up of the same stuff; the same amount of matter (atoms). Weight! Your Weight on Other Worlds: Your mass. o (e.g. Earth, Moon, or space). Try it out sometime! o Mass is! In space you are but not. Calculate Weight =mass x gravitational acceleration Newtons = kg x little g Earth g = 9.8 m/s 2 Moon g = 6 m/s 2 A soccer player has a mass of 45 kg. Calculate the soccer player s weight on Earth and on the Moon. Newton s Second Law Interactive View the interactive and make a prediction. Which person and shopping cart combination will have the greatest acceleration? How does the 2 nd law relate to the 1 st Law? Explain your reasoning. Check for Understanding The same force is applied to each box. If box 1 has a smaller mass than box 2, which one will have the greater acceleration? Circle your answer. 2nd Law (F = ma) How much force is needed to accelerate a 1400 kilogram car 2 m/s 2?

5 Centripetal Forces Circular motion Think about riding in a car Going around a curve smashes you against the window. o This is! You want to keep going, but an outside force turns your body around the curve. Earth and Moon Let s pretend that the gravitational attraction between the Earth and the Moon was turned off! What would happen to the Moon? Draw in a vector(s) for the moon and explain. Gravity Turned ON Gravity Turned OFF The Moon s forward velocity in combination with the gravitational force from the Earth, causes the circular motion of the moon around the Earth. Explain the motion above: Complete Chapter 2 Reading and answer the section questions 1-3 from page 55 below: Rocket Video Which of Newton s Laws explains how a rocket takes-off? 1 st 2 nd 3 rd Who is considered the father of the modern-day rocket? Newton's Third Law All forces come in. For every there is an and.

6 How do action-reaction force pairs help you stand up? Explain. Describe 6 real-life scenarios and explain the action-reaction force pairs. Example 1 - Sitting in a Chair. Example 2 Hitting a baseball with a bat Example 3 A car driving on the road. Example 4: A bird flying through the air. Example 5: A fish swimming through water. Example 6: A rocket blasting off to space. Astronauts in Space - View the PowerPoint and watch the video. Why is it difficult for astronauts to move around in space? Challenge Question How does a jellyfish move up and down in the water? Illustrate your explanation with vectors. (Hint: Look at page 57 in your textbook.) Complete Chapter 3 Reading and answer the section questions 1-3 from page 61 below: