Friday 19 Nov:

L# 23: 1-4, 8, 13, 15, 16, 18, 20   Due Today Fri 19 Nov

(Center of Mass)

Review Monday 22 Nov

Test  L# 19 - 23  Tues 23 Nov

Journal: Find center of gravity

Torque Problem (from lower left corner):

(x axis: Center of Gravity is CCWt)

CCWt = CWt + CWt

   Fd  =  Fd  + Fd

132x = (100)(5) + (32)(14)

132x = (500) + (448)

x = 948/132 = 7.18

(y axis: Center of Gravity is CWt)

CWt = CCWt + CCWt

   Fd  =  Fd  + Fd

132y = (100)(5) + (32)(8)

132y = (500) + (256)

y = 756/132 = 5.73

Count Stamped Homework

Start Review:

A projectile is shot directly upward from the ground at 450 m/s.

1. How long does it take to reach the apex?

2.  How long is it in the air?

3. What is its speed when it hits the ground?

4. What height does it reach?

1. Vertical speed / 10 m/s²

    450m/s / 10 m/s² = 45s

2. 45s up + 45s down = 90s

3. Same height = same speed

i.e., 450 m/s

4. y = (V_o)t + 1/2(a)(t²)

    y = (450m/s)45s + 1/2(-10m/s²)(45s²)

    y = (20,250m) - (5m/s²)(2025s²)

     y = (20,250m) - (10,125m)

                y = 10,125m

Simple Machine Project:

Requirements:

1. Individual

2. Build and its due Wed 24 Nov

(must be made and not just a store example)

2. Any size & any of the 6 types you want.

(as long as you can carry it by your self through the doorway)

3. One page paper explaining your simple machine and its use in History

. Bridge Contest:

• Due by Friday Dec 17

Tower Contest:

• Due by Friday Jan 7th