PHYSICS 1403, QUIZ 2, Chapter 4, July 18, 2006
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 box of mass m = 25 kg is accelerated by being
pushed across a flat table, using a force F = 50 N, which makes an angle θ
= 30° with the horizontal. Assume that friction can be neglected and that
there is no vertical acceleration. Take the x-axis parallel to the horizontal
direction & the y-axis perpendicular to that surface.
a. Sketch the free body diagram for the mass, properly labeling all forces.
b. Compute the x and y components of the force 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 acceleration a of the box and the normal force FN
on the box due to the table. (Hint: Is the normal force equal and opposite to the
weight?)