Jane is experimenting using the apparatus for this experiment. In the figure below, we see a “snapshot” of the apparatus at one instant during its rotation. What is the direction of the centripetal force and acceleration vectors of the bob (B)?

A) Up B) Down C) to the left D) to the right E) into the page F) out of the page

In a separate trial, Jane determines the period to be 2.14 sec. With the apparatus stopped, she measures the radius to be 13.2 cm and the mass of the bob (B) to be 253 g. What was the centripetal force on the bob, in newtons, while it was in uniform circular motion?

With the rotation of the apparatus stopped, Jane attaches a string and mass holder (W), as shown in the figure. The mass of the mass holder (W) itself is 12.8 g. Using the data collected in PL-4 [period = 2.14 s, radius = 13.2 cm, mass of bob = 253 g], predict how much mass (in grams) Jane will need to add to the mass holder (W) in order to stretch the spring so the bob aligns with the pointer (P).

 

B A