1. 4*6 Forces Acting During Acceleration: Apparent Weight on a Roller Coaster
WDYS??? (p406) .
WDYT???
Your weight (does/does not) change when you are riding a roller coaster.
If you were sitting on a scale, it (would/would not) give different readings at different places on the roller coaster.

2. 4*6 NOTES: (p410-415) Forces Acting During Acceleration
Using Newton’s 1st and 2nd Law to Explain Forces Acting During Constant Speed and Acceleration
Newton’s 1st Law = Inertia
Newton’s 2nd Law  a = F/m F = m×a m = F/a
Constant velocity = Zero acceleration = NO Fnet
Balanced = NO movement OR at a constant speed
Unbalanced = movement where the vector is longer and the magnitude (#N) is larger

3. A. At constant speed
Constant Speed UP = Constant Speed DOWN = SAME scale reading = Fweight = FN

4. B. Positive acceleration
Acceleration UP = LARGER scale reading = FN is GREATER than Fweight

5. c. Negative Acceleration
Acceleration DOWN = SMALLER scale reading = FN is LESS than Fweight

6. Force = m × a, its units are Newtons (N)
2. Calculating Acceleration
Force = m × a, its units are Newtons (N)
Weight = m × g, its units are Newtons (N)
Therefore, Force = Weight
Free Fall (broken elevator cable)  the scale would NOT push up at all and the reading would be ZERO

7. 4*6 Physics Talk: (p414) Forces Acting During Acceleration
3. Apparent Weight
Normal Force (FN) = Apparent Weight
(FN) = (m × g) + (m × a)
Acceleration UP =
MORE Contact Force =
LARGER “Apparent” Weight =
You feel like you weigh MORE!!!
Acceleration DOWN =
LESS Contact Force =
SMALLER “Apparent” Weight =
You feel like you weigh LESS!!!
Apparent Weight = (m × g) + (m × a)

8. Sample Problems (model)
A man with a mass of 50kg is on an elevator, the elevator is accelerating at +2 m/s/s. What is his apparent weight?

9. Sample Problems (team)
A woman with a mass of 25kg is on an roller coaster, the ride is accelerating at -2 m/s/s. What is her apparent weight?

10. Sample Problems (you)
A kid with a mass of 15 kg is on an elevator, the elevator is accelerating at 3 m/s/s. What is his apparent weight?

11. Free Fall  the ONLY force acting on an object is GRAVITY; (Fweight)
4. Air Resistance
Free Fall  the ONLY force acting on an object is GRAVITY; (Fweight)
Acceleration due to GRAVITY is IDENTICAL for ALL objects falling on Earth…10m/s/s!!!!!
Air Resistance  the force working AGAINST GRAVITY that pushes upward on falling objects; (FN)
***4-6 Cu/PTG***

12. 4*6 TOTD
No movement and constant speed are two examples of __________ forces.
On a free-body diagram, if there is no movement or its at constant speed, then the arrow/forces = _____.
_____ is the unit for both Force and Weight.
One feels _____ when they are moving DOWN in an elevator because they have _____ contact force.
The equation for Apparent Weight = __________.

13. BOOKWORK
4-6 CU (p 415 #1-5; write questions) 4-6 PTG (p. 418, #1-8 skip 4)