1. Vectors
Day 3
Lyzinski Physics

2. Vectors Problem Packet Homework Solutions
(14-18)

3. 14. Resolve the vector at the right into its vertical
and horizontal components.
And so…….
The x-component is km and the y-component is km
Notice that the components are always perpendicular to each other.
45 km y
40o x

4. 15. Wonderwoman, in a feat of super strength, pulls a sled
loaded with 20 kids over the sand at the beach (she’s a
little early for the winter but can’t wait) with a force of
2,000 lbs. The rope makes a 20o angle with the
horizontal. Find the components of the rope.
F =2000 lbs Fy
20o Fx

5. 16. A VW is parked on a hill with a slope of 30o
16. A VW is parked on a hill with a slope of 30o. The car has a downward force of 9,000 newtons. Find the component forces. (Hint: One component is parallel to the slope and the other is perpendicular to the slope).
Part 1
How do we know the two angles shown are congruent?
Notice the 3 right triangles???
30o
Pink + Green = 90o
See next slide for Solution to problem #17

6. Now, let’s find those components 
16. A VW is parked on a hill with a slope of 30o. The car has a downward force of 9,000 newtons. Find the component forces. (Hint: One component is parallel to the slope and the other is perpendicular to the slope).
Part 2
Now, let’s find those components 
30o
9000 N
30o

7. 17. A man pushes a lawn mower with a 500-newton force
17. A man pushes a lawn mower with a 500-newton force. The handle makes a 40o angle with the ground. Find the horizontal and vertical components of his applied force.
???
40o
40o F
[Downward]
[ In motion direction ]

8. 18. Another man pulls a wagon with his son sitting in it
18. Another man pulls a wagon with his son sitting in it. The man pulls the wagon with a force of 200 N at an angle of 40o with the ground. The sidewalk provides 30 N of friction in the opposite direction of the man’s motion. What is the net force on the wagon in the direction parallel to the ground?
40o
friction
40o F + =
123.2 N
[direction of motion]
153.2 N
30 N

9. Vectors Problem’s from Buffa book (pp. 95-96)

11. Day #3

12. commutatively
50 cos(30) = 43.3 km
50sin(30)
= 25 km
-20 – 43.3 = -63.3
0 – 25 = -25

13. Tan-1(25/63.3) = 21.55o 68.1 km [W 21.55o S] 68.1 km [S 68.45o W]

14. 7 m/s [E 20o N]
12 ft [S 43.8o E]
o S of E
7 20o N of E

15. 63.3 25

16. 63.3 25
68.1
21.55o
68.45o
68.1 km [W 21.55o S]
68.1 km [S 68.45o W]

18. 76.60 N
64.28 N
45 N
100 N
200 N
50o
20o N
68.40 N x: y:
-45 – = N
– = N
66.34 N
4.12 N
FNET
FNET = N [E 3.55o S]

19. FNET = 405.4 lb [W 86.5o N] 200 lb 300 lb 400 lb 50o 20o 281.91 lbx: y:
= lb
= lb
FNET = lb [W 86.5o N]

20. 80 N
42 N F3
???o
45o
5 N Fx Fy
29.70 N
114.7 N
29.70 N F3 x: y:
Fx =  Fx = N
Fy =  Fy = 114.7
F3 = N [E 75.5o N]

21. “Day #3 Vectors HW Problems” (from the packet, #’s 19-23)
Tonight’s HW
“Day #3 Vectors HW Problems” (from the packet, #’s 19-23)
Do Buffa, pp , problems 21, 22, 23,