Newton's Second and Third Laws

Question 1

State Newton’s Third Law

Answer 1

For every action, there is an equal but opposite reaction

Question 2

What is an action-reaction pair?

Answer 2

• Force (push or pull)
• pair of forces acting on two interacting objects. The size of the forces are equivalent.

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Question 3

Can you always detect motion?

Answer 3

No, because Earth’s inertia is so great that its acceleration is hard to notice.

Question 4

Do action-reaction forces cancel?

Answer 4

No, because they act on different objects.

Question 5

What happens to balanced forces acting in opposite directions?

Answer 5

It results in no motion.

Question 6

State Newton’s Second Law

Answer 6

• F=ma

- a=f/m

Question 7

• As force increases, acceleration _________

- As mass increases, acceleration _________

Answer 7

• As force increases, acceleration –increases–

- As mass increases, acceleration –decreases–

Question 8

Momentum

Answer 8

the quantity of motion of a moving object, measured as a product of its mass and velocity (p=mv)
notation: kgm/s

Question 9

Conservation of Momentum

Answer 9

the total momentum of the two objects (object 1 plus object 2) is the same before the collision as it is after the collision. The total momentum of the system (the collection of two objects) is conserved. Momentum can only transfer.

Question 10

Give an example of an action reaction pair

Answer 10

Ex. When you jump, you push down on the ground, and the ground pushes you back up so that you can complete your jump.
Other examples:
-gymnast pushes down on vault bar; vault bar pushes gymnast back up so gymnast can complete action
-kayaker’s paddle pulls on the water; water pushes back on the paddle; causing the kayak to move forward
-two people both exert a force on a volleyball simultaneously; the ball exerts and equal force and does not move
-volleyball player exerts force on ball; the ball exerts an equal force, therefore flying up

Question 11

Study the card deck titled “Physics (8)”

Answer 11

This will help you study Newton’s First Law

*Rate yourself on how well you remember Newton’s First Law….

Question 12

What is a motion map?

Answer 12

Motion maps represent position, velocity, and acceleration of an object

Question 13

What symbolizes the origin in a motion map?

Answer 13

x

Question 14

The spacing between velocity vectors in a motion map are equal if….

Answer 14

…velocity is constant

*NOTE: If the velocity vectors are spaced further apart, the faster the object is moving

Question 15

1. Create a motion map that represents a car moving fairly fast at a leftwards constant speed
2. Create a motion map that represents a car moving fairly slow at a rightwards constant speed

Answer 15

1. x—————————————————————->
   ⬅️ ⬅️ ⬅️ ⬅️ ⬅️ ⬅️ ⬅️ ⬅️
2. x————————————————–>
   ↦ ↦ ↦ ↦ ↦ ↦ ↦ ↦ ↦

Question 16

objects at equilibrium have ________ acceleration

Answer 16

no acceleration

Question 17

acceleration

Answer 17

rate at which velocity changes over time

Question 18

force is _____________ proportional to acceleration

Answer 18

directly proportional

Question 19

acceleration is ____________ proportional to mass

Answer 19

inversely porportional

Question 20

1. draw a diagram of a car speeding up to the right

2. draw a diagram of a car slowing down the right

Answer 20

1. .. . . . . . . . . . . . car
2. . . . . . . . . . . .. car

Question 21

velocity

Answer 21

change in speed over time