4.2. Newton’s Second Law http://www.ck12.org
a. Draw a FBD for the person, labeling all forces.
b. What does the scale read when the elevator is at rest?
c. Calculate the acceleration of the person from 5-10 sec.
d. Calculate the acceleration of the person from 10-15 sec. Is the passenger at rest?
e. Calculate the acceleration of the person from 15-20 sec. In what direction is the passenger moving?
f. Is the elevator at rest att= 25 s. Justify your answer.Answers(usingg= 10 m/s^2 ):
- According to Newton’s second law: the acceleration of an object is inversely proportional to it’s mass, so if
you decrease it’s mass while keeping the net force the same, the acceleration will increase. - When you jerk the paper towel, the paper towel that you are holding onto will accelerate much more quickly
than the entire roll causing it to rip. Again, acceleration is inversely proportional to the mass of the object.