1. A wire above a street is strung between two buildings. A 30 kg (weight?) street lamp hangs at
    the center of the wire that dips at 35⁰.
    a) The wire's Fs indicates how tightly the wire was pulled when it was strung.With two
        segments of wire holding the lamp, there are how many Fs's (force within the wire)?
    b) Which components of the Fs's (Fv's or Fh's), attempt to lift the lamp? How do these
         components share the lamp's weight? Therefore, what is their magnitude?
    c) Which components attempt to pull the lamp simultaneously to each side? (and pull the wire
        ends out of their attachment points or pull over the supporting structures?) What is their
        magnitude? Note: it is this force component that tries to pull the wire out straight, i.e., that
        tries to create a 0⁰ dip angle.
    d) Finally, what are the tensions (Fs's) on the two segments of wire on either side of the lamp?
2. Provide the same types of answers as in Q. 1. if a Christmas decoration lamp's mass is 10 kg
   (weight?) and the wire dips at 30⁰.
3. Provide the same types of answers as in Q. 1. if a mirror ball's mass is 5 kg (weight?) and the
    wire dips at 25⁰.
   e) Also, if either wall can withstand an outward tug of 30 N, will they remain standing?
4. Redo Q. 1. with the same mass but change the dip angle to 15⁰. How much more Fs in the wire
    is needed to pull it tighter thus creating the smaller dip? Which angle is safer for the supporting
    walls (which situation has a smaller Fh)?
5. A wire above a street is strung between two poles.
    a) If the tension (Fs) in each of the wire's segments is 200 N and it dips at 27⁰, find the force
        components.
    b) A giant, realistic but fake snowball of what mass can be hung from the wire?
6. As the dip angle changes, the proprtions of the available force (Fs) acting as Fv and as Fh
    change also.
    a) With what size of dip angle is the Fh the larger of the Fs components? Why?
    b) With what size of dip angle is the Fv the larger of the Fs components? Why?
    c) Think: of dip angle and Fh, which controls which? Why?
7. Redo Q. 5. if the dip is reduced to 15⁰ but the tension in each wire segment (Fs) is still 200 N.
    Can a heavier or lighter decoration be supported if the dip is reduced but the Fs is not changed?
    In other words, if less of the available force (Fs) acts as Fh because an object is lighter, and
    more of the available force can therefore act as Fh, what happens to the dip angle?
8. A 70 kg (weight?) store sign is supported at the end of a horizontal metal rod sticking straight
    out from the side of the store. For more support, a wire angles up at 50⁰ from the rod end to a
    hook in the wall above the spot where the rod attaches to it.
    a) What force is in the wire?
    b) What force component is in the rod?
    c) Which force component tries to lift the sign?
    d) Which force component is in the wall itself?
    e) In which direction do their forces operate?
    f) Find the force in the wire (Fs), and the rod (Fh). (Since the sign does not fall, what must be
       the size of Fv?)
9. Provide the same types of answers as in Q. 5. if the sign's mass is 60 kg (weight?) and the wire
    angles up at 45⁰.
10. Provide the same types of answers as in Q. 5. if the sign's mass is 90 kg (weight?) and the
     wire angles up at 60⁰. c) Also, if the wall can withstand an outward tug of 500 N, what will
     happen to the wall?
11. Redo Q. 7 but change the wire angle to 50⁰. How does the angle affect the amount of force on
      the wire? Which angle is safer?
12. A 90 kg mass hangs from a length of rope looped between two facing walls. From the point
     where the mass is attached to the loop, the left rope segment angles up to the wall at 30⁰
     while the right segment angles up at 50⁰. Find the tension in both segments of rope.
13. Redo Q. 12. when the mass is 120 kg, the left up-angle is 50⁰ and the right up-angle is 35⁰.
14. a) Redo Q. 12. when the mass is still 120 kg but the left angle is 55⁰ and the right is 45⁰.
      b) Is there a relationship to the up-angle and the tension in that rope segment?

1. State Newton's Third Law of Motion.
2. Use diagrams to explain the application of this idea in the following situations:
    a)when you are squishing a rubber eraser between your fingers
    b) you are standing on the floor
    c) you are a sprinter accelerating out of the blocks
3. If a 12 N force is applied to an object, it "pushes" back with what force?
4. If the applied (action) force is greater than the "push back" (reaction) force, what happens to
    the object?
5. What if the action force is less than the reaction force?
6. Two tug of war teams are playing on a hard but muddy surface. When Team 1, mass =
    2 500 kg, pulls on the rope, it accelerates at 0.9 m/s² toward Team 2 whose mass is 2 900 kg.
   What happens to Team 2?
7. Brutus and Brutette are having a shoving match on ice. When Brutette, mass = 55 kg, pushes at
    Brute, mass = 70 kg, she accelerates away at 1.2 m/s². What happens to Brute?
8. A 90 kg astronaut pushes with 30 N at a 2 000 kg satellite. If the astronaut accelerates away
    at 2.7 m/s², what happens to the satellite?
9. A 60 kg person stands in an elevator. a) What is their weight?
    b) If the elevator accelerates up at 1.5 m/s², what happens to the person's weight? Why?
    c) What is their weight if it accelerates up at 2.5 m/s²?
10. a) What happens to their weight when the elevator accelerates down at 1.7 m/s²?
      b) What happens to their weight if it accelerates down at 3.6 m/s²?
      c) What happens to their mass?
11. A length of rope is looped over a pulley wheel. On the left end of the rope hangs a 4 kg mass
      while on the right end hangs a 6 kg mass.
      a) In which direction does the rope and masses move?
      b) Find the tension in the rope.
      c) At what rate will it then accelerate down?
12. Redo Q. 11. with 4 and 8 kg as the left and right masses.
13. Redo Q. 11. with 5 and 9 kg as the left and right masses.