From the given information, the only thing we can tell is the wave's speed ... 21 m/s .
That also happens to be the product of it's (frequency) x (wavelength), but we can't say what either one alone is.
None of the items listed can be calculated without more information.
Answer:
B)ωf = 1.8 rad/s
Explanation:
Given that
I= 2 kg.m²
d= 30 cm ,r= 15 cm
F= 4 N
t= 6 s
The torque produce by force F about point center of disc
T= F .r
T= 4 x 0.15 = 0.6 N.m
Lets take angular acceleration of the disc is α rad/s²
T= I α
0.6 = α x 2
α= 0.3 rad/s²
We know that
ωf = ωi + α t
ω =Angular speed of the disc
Initial angular speed ωi = 0 rad/s
ωf = 0 + 0.3 x 6
ωf = 1.8 rad/s
Therefore the answer is B.
I strongly believe that it is C just because this could not actually occur so the only thing that could happen is that she didn't talk as quietly as she thought she did.
Hope I helped!!!!
Only units of the SI and those units recognized for use with the SI are used to express the values of quantities. Equivalent values in other units are given in parentheses following values in acceptable units only when deemed necessary for the intended audience.