PHYSICS 1403, QUIZ 2
Chapter 4, July 20, 2005
Partial credit will be LIBERAL, provided that you show your work!
USE BACK IF NECESSARY! (Please tell me you have done so!)
Name: ______________________
1. (10 points) Newton’s Laws
a.
Using complete, grammatically correct English sentences, state Newton’s 1st Law of Motion.
b.
Using complete, grammatically correct English sentences, state Newton’s 3rd Law of Motion.
2. (20 points) See figure. A mass m = 32 kg at the origin is acted on by two forces
which make a 120° angle with each other. F2 = 18 N and is directed along the
positive y-axis. F1 = 12 N and is directed as is shown.
a. In the coordinate system shown, compute the x and y components of F1 and
F2. (Caution!! Note that the angle that F1 makes with the x-axis is NOT 120º!!)
m = 32 kg
b. Use the analytic (trig) method of vector addition to compute the x and y components of
the resultant force F = F1 + F2 and the magnitude and direction of F.
c. Write the two equations which result by applying Newton’s 2nd Law to this problem in
the x and y directions. (Writing them in symbols, without substituting in numbers, will
receive more credit than writing them with numbers substituted in!)
d. Use the equations of part c to find the x and y components of the acceleration
of the mass. Also find the magnitude and direction of this acceleration.