FPC Day 30

Free Body Diagrams and Mass v Weight

Warm Up

• If an object is flying through the air, draw arrows on this picture to represent the forces acting on it.

OBJECT

Agenda

• Free Body Diagrams• Mass v Weight

• Homework: Reading Kinematics 3.2, 3.3, 4.1 & 4.2

Due Wednesday, 11/19(Already done? Have it out during seat work

today)

Learning Target: Newton’s 2nd Law

5

Free Body Diagrams

• These are used to show all of the forces acting upon an object so you can determine the NET FORCE and how it will affect the objects motion

• Net Force: is the sum of all the forces acting upon an object.

*Balanced or Unbalanced?

• Redraw the object with the net force?

• Are the forces on the object balanced or unbalanced?

• What is the motion of the object?

15 N

20 N

The object is initially at rest

Net Force= 5 N

Quick Tutorial Video Than Practice• Get out iPad or Computer• Go to the URL or Scan QR Code on

sheet• Watch video (use head phones if you

have them)– See how Free Body Diagrams are drawn–When done start try 1st one on sheet– Raise hand when done and I will check

it

Free Body Diagrams PracticeDO1. Complete ALL the steps for each problem on

the right hand side2. Work together to ask each other questions3. I will be calling on random group members to

explain problems to me

DONE BY 20 minutes

WHEN DONE raise your hand to show your teacher

Set Up Cornell Notes: Right hand Side

• Title: Mass versus Weight

• Write down three things from the video: Mass vs. Weight

Mass versus Weight

Mass• How many particles

are packed into an object

• Units: grams or kilograms

Weight• The measurement of

gravity’s pull on an object• Is a force

• Fgravity=mass * agravity

– Gravity = 9.8 m/s/s• Units: NewtonsRemember if you want to lose

weight go to the moon!

Converting Pounds (lb) to Kilograms (kg.)

1 Pound (lb) = 0.45 Kilograms (kg) 1 Kilogram (kg) = 2.2 Pounds (lb)

120 lb * 0.45 kg 1

lb

= 54 kg

What is 1 car____ ?1 steering

wheel

What is 1 ?1

What is 1 steering wheel ?1

car What is 1 car____ ?

4 wheels3 cars * 4 wheels____?

1 car

1 lb * 0.45 kg1 lb

= .45 kg

2 lb * 0.45 kg 1 lb

= .90 kg

1 kg * 2.2 lb 1 kg

= 2.2 lb

2 kg * 2.2 lb 1 kg

= 4.4 lb

120 kg * 2.2 lb 1 kg

= 264 lb

Write this down in notes

= 12 cars

Practice in your notebook

• A soccer ball has a mass of 0.43 kg, what is its weight in lb?

• A Ferrari has a mass of 1100 kg, what is its weight in lb?

• The average weight of a Boston terrier is 18 lb Calculate the mass in kg.

• Calculate your mass in kg!