Seesaws

Question 1

How does a balanced seesaw move?

Answer 1

It rotates steadily on a fixed axis

Question 2

What types of motion are there?

Answer 2

Translational (location) and rotational (rotation)

Question 3

Give two aspects of rotation (hint: angular)

Answer 3

angular position: an object’s oritentation

angular velocity: the rate at which an object’s angular position is changing with time

Question 4

What is the curled right hand rule?

Answer 4

1- curl fingers in direction of rotation

2- thumb shows official direction

Question 5

What is torque?

Answer 5

Twisting force that disrupts rotational inertia

Question 6

What is Newton’s 1st Law of Rotational Motion?

Answer 6

A rigid object that is not wobbling and that is free of external torques rotates at constant angular velocity

Question 7

Why does a seesaw need a pivot?

Answer 7

The pivot prevents the seesaw from undergoing translational motion, while leaving it free to undergo rotational motion.

Question 8

What is center of rotation?

Answer 8

The point about which all the physical quantities of rotational motion are defined

Question 9

Why does a lone seesaw ride plummet to the ground?

Answer 9

The lone rider produces a torque on the seesaw that causes it to undergo angular acceleration

Question 10

What is rotational mass?

Answer 10

The measure of an object’s rotational inertia

Question 11

What is Newton’s 2nd Law of Rotational Motion?

Answer 11

Angular acceleration = net torque / rotational mass

Question 12

Is it possible to produce force and not torque?

Answer 12

Yes, for example pulling on a door that needs to be pushed.

Question 13

What is a lever arm?

Answer 13

Perpendicular distance to force and torque

Question 14

What is the second right hand rule?

Answer 14

1- do a pointing motion on the lever arm
2- rotate to force
3- thumb will be pointing towards torque

Question 15

How can we measure torque?

Answer 15

Torque = lever arm * force

Question 16

Why do the rider’s weight and positions affect the seesaw’s motion?

Answer 16

They affect the net torque on the seesaw and therefore the seesaw’s angular acceleration

Question 17

What is balanced in physics?

Answer 17

Experiencing zero torque due to gravity.

Question 18

What is center of gravity?

Answer 18

The effective location of an object’s weight. On earth, it is the same as your center of mass.

Question 19

Why do the rider’s distance from the pivot affect the seesaw’s responsiveness?

Answer 19

The farther the rider’s masses from the pivot, the greater the seesaw’s overall rotational mass, the slower its angular acceleration

Question 20

How do the seesaw rider’s affect one another?

Answer 20

They support one another and they exchange energy as they seesaw back-and-forth.

Question 21

What is Newton’s Third Law of Rotational Motion?

Answer 21

For every torque exerted, there is an equal oppositely directed torque exerted.

Question 22

What is the formula for work?

Answer 22

Force * distance