1. Ch 7
Objective
Warm-Up
You will learn about circular acceleration and Force
You will learn to use Newton’s Universal Gravitation formula
You will learn about torque
If an astronaut floats in space, then, is there gravity in space?

2. Circular Acceleration
Example: pg 235

3. Exit Ticket
HW: Pg

4. Ch 7
Objective
Warm-Up
You will learn about circular acceleration and Force
You will learn to use Newton’s Universal Gravitation formula
You will learn about torque
Get Out HW

5. Example: pg 237
Circular Force

6. Exit Ticket
HW: Pg

7. Ch 7
Objective
Warm-Up
You will learn about circular acceleration and Force
You will learn to use Newton’s Universal Gravitation formula
You will learn about torque
Get Out HW

8. The Universal Law of Gravity
Law of universal gravitation:
Everything pulls on everything else.
Every body attracts every other body with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance separating them.
There is a gravitational force between any 2 objects, regardless of what separates them.

9. The Universal Gravitational Constant, G
Examples:
The greater the masses m1 and m2 of two bodies, the greater the force of attraction between them.
The greater the distance of separation d, the weaker the force of attraction.
Gravity is the weakest of four known fundamental forces
With the gravitational constant G, we have the equation
Universal gravitational constant:
G = 6.67  Nm2/kg2
Once the value was known, the mass of Earth was calculated as 6  1024 kg

10. Weight and Weightlessness
force an object exerts against a supporting surface
Examples:
standing on a scale in an elevator accelerating downward, less compression in scale springs; weight is less
standing on a scale in an elevator accelerating upward, more compression in scale springs; weight is greater
at constant speed in an elevator, no change in weight

11. Weight and Weightlessness
no support force, as in free fall
Example: Astronauts in orbit are without support forces and are in a continual state of weightlessness.

12. Weight and Weightlessness

13. Exit Ticket
HW: Pg

14. Spinning tops wobble (precess) when they are tilted because they experience a torque due to their weight. The rotation axis of the Earth wobbles in space due to the torque the Sun’s gravity exerts on the non-spherical shape of the Earth. In this lab, we will explore Newton’s Second Law for rotating objects and the resulting precessional motion by studying the gyroscope.
Demo
 This spinning top is a very simple example of a gyroscope.