Answer:
The mass of the ball is 1.360 kilograms.
Explanation:
By Work-Energy Theorem, gravitational potential energy (
), in joules, is the product of weight of the ball (
), in newtons, and height (
), in meters. Please notice that weight is the product of the mass of the ball (
) and gravitational acceleration (
), in meters per square second. Then, the formula for the mass of the ball is:
(1)
If we know that 
, 
and 
, then the mass of the ball is:
The mass of the ball is 1.360 kilograms.
Answer:
The human ear is not sensitive to every frequency of sound, rather, our hearing range is from 20Hz to 20,000Hz. This means sound frequencies outside this range are not audible to the human ear, which is why not every sound produced is heard. This is quite a blessing because if we could hear every vibrating body, then our ears would never stop listening: we won't be able to distinguish 'important sounds' from unimportant ones, rendering our ears effectively useless. Perhaps this is why we have a hearing range in the first place: sounds of our friends and our foes lie in 20Hz-20kHz range.
Answer:
v = 15 m / s
Explanation:
In this exercise we are given the position function
x = 5 t²
and we are asked for the average velocity in an interval between t = 0 and t= 3 s, which is defined by the displacement between the time interval
let's look for the displacements
t = 0 x₀ = 0 m
t = 3 
= 5 3 2
x_{f} = 45 m
we substitute
v = 15 m / s
A > Is the correct answer :)
