Monday 15 Nov:

Journal:

• Atoms at absolute zero has no movement.

• A force acting on an object does work even if the object does not move.

• Energy is destroyed in transformations from one type to another. 

• All Energy can be recycled.

Review:

1. A pendulum (Weight = 10N) has a tension of 30N at the bottom of the swing. What is its

(a) Centripetal Acceleration (in m/s² and in g's)

(b) F_c

2.

a.) What is the tangential Velocity of a horizontal circling 4kg object if radius was 8m and acceleration is 50 m/s²?

b) What is the force required to give this velocity?

Answers:

(a) Net force( F_c) = T-W = ma_c

                       30-10 = 1a_c 

                    a_c =  20 =   20 m/s²    or   2g's

(b) F_c = ma_c  

              F_c = (1kg)(20N/kg)  = 20N

_or  F_c = T -mg  --> 30 - 1(10) = 20N

2) a)

 a_c = v²/r

  50 m/s² =  v²/8m

       v² = 50 / 8 --> V = 2.5 m/s

b) F_c =ma_c   --> (4kg)(2.5²m/s² ) / 8m

   F_c = 3.125N

Quiz Free Response Q's

Go over Pre-Test 6-10 

MOMENTUM

We DEFINE momentum as

(mass) x (velocity) and it's SI units are kgm/s

Momentum is Conserved!!!

(i.e., Initial Momentum = Final Momentum)

Test Ch 7-10 Thursday/Friday!!! 

Test Equations Wed 17 Nov

1.     (Velocity after a period of time)

V_f  =  V_o + at

2.      (Distance after a period of time)

X_f = V_ot  + 1/2 at²

3. (Velocity/distance/acceleration without time)

V_f² =  V_o² + 2aDX

4.    (center seeking acceleration or centripetal acceleration)

A_c = V² / r

5.     (Kinetic Energy)

KE = 1/2mV ² 

6.      (Change of momentum (Dr )=  Impulse)

D(mV) = D(f)(t)

7.      (Power with work)

P_avg =  W/t

8.      (Power with velocity)

P = F(V)

9.      (Force exerted by a springy)

F_s = KX

10.  (Potential energy of a spring)

U_s = 1/2kx²

11.  (period of a spring)

T_s = 2p √ (m/k)

12.  (period of a pendulum)

T_p = 2p √ (L/g)    or    2√ L

13.   (relationship between period and frequency)

T = 1/f

14.  (Newton’s Law of Gravitation)

F_g = G (m₁m₂ ) / r²

15.  Pressure (with atmosphere) of a liquid

 P = p_o  + r g h

16.  (Force of buoyancy)

F_buoy =  weight of Liq displaced = mg = rVg

17.  (Equation of continuity for a liquid)

A₁V₁ =  A₂V₂

18.      (Work & Energy)

 W = DPE + DKE

19.  (Bernoulli's Equation)

P₁ + rgy₁ + 1/2rv₁²  = P₂ + rgy₂ + 1/2rv₂²

20.  (Relationship of

        Press, Volume, Temp of a gas)

(P₁V₁) / T₁  =  (P₂V₂) / T₂

21.    (center seeking force)

 F_c =  Net force = m(V² / r)

22.    (Flow rate: v )

v = Volume/Time

Correct Free Response Q's

Go over Pre-Test 6-10