1.2 Newton’s Laws Re-test Review Grab your journals. Find a partner or group of 3 and sit together with your journals out.

An elevator suspended by a vertical cable is moving downward but slowing down. The tension of the cable must be In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below An elevator suspended by a vertical cable is moving downward but slowing down. The tension of the cable must be a.Less than the weight of the elevator b.Greater than the weight of the elevator c.Equal to the weight of the elevator

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is……B 1.Draw a free body diagram!!!! 2.Because the elevator is slowing down, you know the F N has to be greater than F g

An object of weight W is in freefall close to the surface of Earth. The magnitude of that force that the object exerts on Earth is In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below An object of weight W is in freefall close to the surface of Earth. The magnitude of that force that the object exerts on Earth is a.Zero b.Less than W c.Greater than W d.Equal to W

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is…..D 1.Remember, magnitude is just a number, this question is talking about the FORCE 2.Newton’s 3 rd law states for every action force there is an equal and opposite reaction force 3.The force is equal between the object and Earth, but opposite in direction

An object of mass m rests on a flat table. The earth pulls on this object with a force of magnitude mg. What is the reaction force to this pull? In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below An object of mass m rests on a flat table. The earth pulls on this object with a force of magnitude mg. What is the reaction force to this pull? a.The object pushing down on the table with force mg b.The object pulling upward on the Earth with force mg c.The table pushing up on the object with force mg d.The table pulling upward on the Earth with force mg

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is….B 1.Identify the two objects (object and Earth) 2.The question states Earth pulls on the object 3.Switch out your objects so your reaction force will be the object pulls on Earth 4.We know gravity pulls down, so the opposite force should be pulling up

A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical force that the pole exerts on the fireman. When the force on his hands equals his weight, what happens to the fireman? In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A fireman is sliding down a fire pole. As he speeds up, he tightens his grip on the pole, thus increasing the vertical force that the pole exerts on the fireman. When the force on his hands equals his weight, what happens to the fireman? a.The fireman descends with a smaller but non-zero acceleration b.The fireman continues to descend, but with constant speed c.The fireman descends with slower and slower speed d.The fireman comes to a stop

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is….B 1.Draw a free body diagram!!!!! 2.If the vertical frictional force equals his weight, his net force equals zero 3.If net force equals zero, then the he has no acceleration and his speed is constant

A person is using a rope to lower a 5.0 N bucket into a well with a constant speed of 2.0 m/s. What is the magnitude of the force exerted by the rope on the bucket? In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A person is using a rope to lower a 5.0 N bucket into a well with a constant speed of 2.0 m/s. What is the magnitude of the force exerted by the rope on the bucket? a.10 N b.0.00 N c.5.0 N d.49 N

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is…. C Newton’s 3 rd law (for every action force, there is an equal and opposite reaction force) The bucket is exerting a 5.0 N force on the rope So the rope must be exerting an equal and opposite force on the bucket….which would be 5.0 N If it had asked about NET force, the answer would have been 0.00 N because it is moving at constant speed.

A person who normally weighs 700 N is riding in an elevator that is moving upward, but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read? In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A person who normally weighs 700 N is riding in an elevator that is moving upward, but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read? a.700 N b.Less than 700 N c.More than 700 N d.It could be more or less than 700 N, depending on whether the magnitude of the acceleration is greater than or less than 9.8 m/s 2

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is …… B 1.Draw a free body diagram!!!! 2.Because the elevator is slowing down, the acceleration must be negative (towards the downward direction) 3.That means net force must be negative (towards the downward direction) 4.F net = ΣF

A block is on a frictionless table on earth. The block accelerates at 5.3 m/s 2 when a 10 N horizontal force is applied to it. The block and table are set up on the Moon, where the acceleration due to gravity is 1.62 m/s 2. A horizontal force of 5 N is now applied to the block when it is on the Moon. The acceleration imparted to the block by this force is closest to In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A block is on a frictionless table on earth. The block accelerates at 5.3 m/s 2 when a 10 N horizontal force is applied to it. The block and table are set up on the Moon, where the acceleration due to gravity is 1.62 m/s 2. A horizontal force of 5 N is now applied to the block when it is on the Moon. The acceleration imparted to the block by this force is closest to a.3.2 m/s 2 b. 2.4 m/s 2 c. 2.7 m/s 2 d. 2.9

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is ….. C 1.Acceleration due to gravity is extra information 2.You know that the Force on Earth is 10 N, then the force on the moon is 5 N 3.Force and acceleration are directly proportional 4.If the force is halved, then the acceleration must also half

On its own, a tow truck has a maximum acceleration of 3.0 m/s 2. What will be its maximum acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass? In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below On its own, a tow truck has a maximum acceleration of 3.0 m/s 2. What will be its maximum acceleration when the truck is using a light horizontal chain to tow a bus of twice its own mass? a.2.0 m/s 2 b.1.0 m/s 2 c.1.5 m/s 2 d.2.5 m/s 2

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is….. B 1.F = ma 2.If you keep the force the same, and increase the mass, you would have to decrease the acceleration 3.Because you are adding a bus 2x the mass of the tow truck, the total mass of the tow truck with the bus is 3 4.If the mass increase by 3, the acceleration would have to decrease by 3

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor… In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor… a.Behind the midpoint of the ceiling b.Exactly below the midpoint of the ceiling c.Ahead of the midpoint of the ceiling d.More information is needed to solve this problem

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is ….. B The truck is at constant velocity Everything on the truck is moving at constant velocity The same velocity as the truck If something falls from the ceiling, it’s all going the same speed and its within the system so it hits the floor directly below from where it fell.

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that…. In your journal, explain what this question is asking, what concepts you need to understand to answer this question, and what your answer to this question is.

Swap your journal with your partner, or within your group of 3 Provide feedback to this person. Are they understanding what the question is asking, do they know what concepts are used to answer this question and did they answer this correctly or how you answered.

Swap journals back to their original owners and answer the question with the multiple choice below A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that…. a.The milk carton has inertia b.The milk carton has inertia c.Gravity tends to hold the milk carton secure d.There is an action-reaction pair of forces

In your group (partnership) discuss… What did you miss? What did you do right? What did you do wrong?

And the answer is…. B Remember!!! Inertia is the resistance to change The milk carton is at rest and wants to stay at rest Even though the paper is being yanked out from under the carton, the carton wants to keep is the same spot