Final evaluation exam
Fundamental :
I- To calculate the Earth's acceleration (gravity) g using a pendelum, we measure the length of the pendelum l and the period of oscillation T, and then use the formula: T = 2.π√(l/g)
with l = 1,552 ± 0.002 [m] and T = 2,50 ± 0,02 [s]
Evaluate g with its relative and absolute uncertainties ?
The relation is given: g = g0/(1+h/R)² where g and g0 are accelerations and h,R are distances.
Calculate the relative uncertainty of g in terms of Δg0, Δh and ΔR.
II- We consider an iron ball falling freely from the following distances of 10 cm, 40 cm, and 90 cm, during the following times, 100 ms, 200 s, and 300 s.
Calculate instantaneous velocities?
What do you conclude?
The solution:
II-1. Instantaneous velocity is the distance during the time:
Vinst1= X1/t1=0.1/0.1=1 m/s
Vinst2= X1/t1=0.4/0.2=2 m/s
Vinst3= X1/t1=0.9/0.3=3 m/s
II-2. We conclude that the velocity of the iron ball increases instantaneously from 1 m/s to 3 m/s, which means that the motion is Rectilinear Uniformly Accelerated Motion (RUAM)