Show Question Details in the lab manual and select your prediction here and writ
ID: 1370679 • Letter: S
Question
Show Question Details in the lab manual and select your prediction here and write them down in your lab manual for the situation described. Your TA will come by during the first few minutes of lab and check that you have written your prediction your lab manual. Since the length of the pendulum L and the acceleration of free fall g describe the pendulum period, we should measure the period of the pendulums of different lengths and different masses m. Since we are expecting a simple relation between the period and the ratio of length to gravity, 2 measurements for which the ratio of L/m is the same for each bob will suffice (you can draw a straight line through 2 points). Since the period of the pendulum depends on the initial angle of the launch, we should fix the length of the pendulum and measure the period for several different launch angles. We can then extract all missing parameters from these data. Since the length of the pendulum L is the only physical parameter describing the pendulum period that we can control in the lab, we can measure the period of the pendulum for different lengths. Since we are expecting a linear relation between the period and the length 2 different lengths measurements will suffice (you can draw a straight line through 2 points). Since the length of the pendulum L is the only physical parameter describing the pendulum period that we can control in the lab, we can measure the period of the pendulum for different lengths. To distinguish various functional dependencies (straight line vs. parabola for example) we would need at least 3 different lengths.Explanation / Answer
time period of a pendulum=T=2*pi*sqrt(L/g)
where g=acceleration due to gravity
L=length of the pendulum
so T^2 is directly proportional to L .
but this particular relation is satisfied only for small launch angles. hence assuming we just know that for small angles a particular relationship will emerge, we can take pendulums of different lengths and find out their time period and plot T^2 vs L. (or T vs sqrt(L), whichever you wish).
assuming you dont know that this is going to be striaght line function, minimum three measuments will suffice to prove that it is a linear relation and not parabolic or any higher order relationship
hence option 4 is correct.