Have a Seat and get out your vocabulary Vocabulary will be checked for a completion grade!!!!!!! Have it out or it is a ZERO!!!!!!!!!!!! Vocab quiz is on the next slide, please be patient as I walk around and check that you did your vocabulary.

Vocab Quiz When the net force on an object is not equal to Zero, the forces are ______________________. The type of friction of a stationary object is called ____________________. When an object that is still and wants to remain still, and an object in motion wants to stay in motion, this is describing __________________ 9.8m/s2 is the acceleration due to _______________. When an object if falling and slows down because of the air this is called ____________________________. The velocity an object reaches when air resistance slows it down is called __________________________.

Unit 3 Study Guide Forces!!!

Question 1 You are riding in a car and the driver slams on the breaks. Your body leans forward. Why?

Question 2 A man was pushing a box across the floor and the box started to accelerate. Why did this happen?

Question 3 A rock was thrown off a cliff and as it landed it did great damage to the car at the bottom of the cliff. Why?

Question 4 How much force is needed to accelerate a 75 kg rider and her 225 kg motorcycle at 4 m/s2?

Question 5 What is the velocity of this car?

Question 6 Newton's second law states that F = m x a (Force is mass times acceleration). Which example would have the LEAST acceleration? 25kg rock pushed with a force of 100N 50kg rock pushed with a force of 200N 10kg rock pushed with a force of 20N 30kg rock pushed with a force of 120N

Question 7 An astronaut throws a football in space, what happens to the ball and the astronaut?

Question 8 Consider a situation where you are playing air hockey with a friend. The table shoots small streams of air upward to keep the puck afloat. When you barely tap the puck forward, the puck moves at a constant velocity. What is the purpose of the small streams of air?

Question 9 When you step out of a boat onto a dock, you move forward and the boat moves backward, what law explains this? What is the action force? What is the reaction force?

Question 10 A high tech camera was dropped from a plane and programmed to take a picture every second and records the altitude at which the pictures are taken, what do the scientists notice about the pictures taken?

Question 11 What is the weight of a man whose mass is 56kg and he is on earth?

Question 12 What must occur for a toy car that is at rest to move forward? Why does a persons weight decrease as they climb a mountain on earth?

Question 13 What is a change in position called? Give an example of someone’s velocity. Give an example of someone’s speed.

Question 14 A calculator is left on the table in the classroom, when the students return the calculator has not moved, why?

Question 15 Which statement is true? Weight is constant no matter where you are. Mass changes from the earth to the moon Mass depends on gravity Weight depends on gravity

Question 16 In order to maintain constant acceleration, what must happen to the force when the mass is doubled? What kind of relationship is represented?

Question 17 A 15 kg book is moved at an acceleration of 4m/s2 , what force is needed to accomplish this?

Question 18 Which of the following best describes a balanced force? A ball rolling at a constant velocity A ball accelerates rolling down a hill A ball bounces off the rim of the basketball goal A ball slows down rolling over gravel

Question 19 What are two examples of forces? How do forces affect the motion of objects?

Question 20 Cody and Devin are pushing barrels up a hill, Cody’s barrel has a mass twice that of Devins’. What must Cody do to reach the top of the hill at the same time?

Question 21 Is the following statement true of false? A penny falling from the top of the empire state building is going to fall at a constant velocity

Question 22 Why do all objects accelerate towards the earth? List 4 types of friction and give an example of each.

Question 23 Chris and Taylor are pushing on a book that is sitting on a table. Chris is using 10N of force and Taylor is using 7N of force in the opposite direction. Draw a force diagram for the situation and calculate the net force. Are the forces balanced or unbalanced?