What is the difference between models I and II? I. II. What is the difference between models I and II? I includes negative particles (electrons) while II does not I says that the overall charge of an atom is neutral while II does not. I says that atoms are not made of smaller parts while II does I says that the positive charge is spread out while II says it is in the nucleus D

Which of the above are ions? Which of the above are neutral atoms? D A B C Cl 35 17 -1 Rn 222 86   +1 K 39 19 S 32 16 -2 E. 17 protons, 18 neutrons, 17 electrons F. 6 protons, 8 neutrons, 6 electrons G. 8 protons, 8 neutrons, 10 electrons H. 7 protons, 7 neutrons, 10 electrons Which of the above are ions? Which of the above are neutral atoms? Which of the above are the same element? Which of the above have the same atomic mass? Which of the above have the same charge? Ions: A, C, D, G, H Neutral atoms: B, E, F Same element: A and E Same mass: A and E; F and H Same charge: D and G (and all neutral atoms have zero charge)

A neutral balloon is attracted to a mystery object A neutral balloon is attracted to a mystery object. The mystery object’s charge is: Positive Negative Neutral Unknown D: unknown

Super Fun Mystery Object A ???? Super Fun Mystery Object A is A. Positively Charged B. Negatively Charged C. Neutral D. Cannot Be Determined   Neutral electroscope A

Object A attracts to positively charged Object B and has no reaction with neutral Object C. What is the charge on Object A? Neutral

Objects become positively charged by Gaining a proton Losing a proton Gaining an electron Losing an electron D

The resistance of the LB is 18 ohms The resistance of the LB is 18 ohms. What is the current through points A and B? A is 9 C/s and B is 0 C/s A is 0.5 C/s and B is 0 C/s A and B are both 0.5 C/s A and B are both 9 C/s A B 9V C

Which light bulbs are lit? 1 2 3 +  - LB 1 and LB 2

LB1 is 12 ohms and LB2 is 36 ohms. The battery is 18 V. How many joules does LB 1 take from each coulomb? What is the current at point A? What is the current at point D? What is the current at point G? B A C D E G F 1 2 LB 1 takes 12 J from each coulomb Current at A is 1.5 amps Current at D is 0.5 amps Current at G is 2 amps

LB1 takes 6 J from each coulomb and LB3 takes 8 J from each coulomb. What is the voltage of the battery? The current at point d is 2 coulombs per second. How many Joules does LB 2 give off each second? 1 2 3 a d f b e c Battery V = 14 V LB2 P = 8 J/C * 2 C/s = 16 J/s

All three circuits have the same battery voltage and all of the light bulbs have the same resistance. Which circuit has the greatest current by the battery? 1 Circuit 1 2 3 Circuit 2 2 3 Circuit 3 Circuit 3

What is the resistance of LB 3? The battery is 9 V, the resistance of LB 2 is 6 ohms, and the current through point D is 1 coulomb per second. What is the resistance of LB 3? How many joules are carried by the coulombs through point A? A B C G F 1 2 3 D E V2 = 6*1 = 6 V; V3 = 3 V. R3 = 3 V/1 amp = 3 ohms 0 J at point A (after LB1)

Which direction (positive or negative) is the total force in graph H? P(m) A P(m) B P(m) D C P(m) E P(m) P(m) G P(m) H Which of the above position-time graphs show an object with balanced forces? Which direction (positive or negative) is the total force in graph H? F Balanced: A, B, C, D Graph H: total force is negative (speeding up, negative)

What is the direction of the total force in graph D? V(m/s) A V(m/s) V(m/s) C V(m/s) D V(m/s) E B V(m/s) F Which of the above velocity-time graphs shows an object with unbalanced forces? What is the direction of the total force in graph D? G Unbalanced: C, D, E, F Total force in Graph D: negative (slowing down, positive)

A sled has the FBD to the right A sled has the FBD to the right. If the mass of the sled (including anything on it) is 50 kg and the change in velocity is -3 m/s/s, what is the force by the dogs? F On sled By ground By Earth (Gravity) By friction (20 N) By dogs Ftotal = m * a = 50 kg * (-3 m/s/s) = -150 N Ftotal = Fdog + F friction -150 N = Fdog + 20 N Fdog = -170 N

After 5 seconds, the velocity of the car is 20 m/s After 5 seconds, the velocity of the car is 20 m/s. What is the change in velocity every second? If the car has a mass of 15 kg, what is the total force on the car? V(m/s) a = 20m/s/5s = 4 m/s/s Ftotal = m*a = 15 kg * 4 m/s/s = 60 N

An old 8 kg cart is initially at rest when pulled to the left with a force of 12 N in magnitude. Friction pulls on the cart with a force of 4 N in magnitude. What is the change in velocity for every second? What happens once the person lets go of the cart? Sticky track Old Cart Ftotal = -12 N + 4 N = -8 N a = Ftotal/m = -8 N/8 kg = -1 m/s/s Cart slows down because of friction