Solving Pendulum Question on Physics Quiz: Length 2m, 10 Oscillations in 32 secs

  • Thread starter Thread starter NoHeart
  • Start date Start date
  • Tags Tags
    Pendulum
AI Thread Summary
The discussion revolves around calculating the gravitational acceleration on a moon using the formula g=4π²L/T², given a pendulum length of 2m and a period derived from 10 oscillations in 32 seconds. The initial calculation incorrectly uses a period of 3.125 seconds instead of the correct 3.2 seconds. This mistake leads to an incorrect value for gravity, which does not match any of the provided answer choices. The correct approach confirms that the period should be calculated as T=t/r=32/10=3.2 seconds. Thus, the correct value for gravity can be determined by properly substituting this period into the formula.
NoHeart
Messages
28
Reaction score
0
I'm having a problem with just one question on this week's physics quiz-
a pendulum with length 2m on a moon oscillates 10 times in 32 seconds, what is the gravity on this moon?

i know (or thought i knew) how to get the answer to this, with the simple formula g=4pi^2L/T^2

10 oscillations in 32 seconds means a frequency of .32Hz, right? and T=1/f so T=3.125, right?
so when i plug in T as 3.125 and L as 2, i get an answer of 8.08 m/s^2

this is not one of the answer choices, however. my choices are 2.54, 9.86, 7.71, and 3.86
what have i done wrong?
 
Physics news on Phys.org
Your approach is correct, Your arithmetic is wrong. The Period would be equal to 3.2
 
10 oscillations in 32 seconds means a frequency of .32Hz, right? and T=1/f so T=3.125, right?
Actually,you are not right.
T=t/r=32/10=3.2 second.
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top