it is generated by two objects pushing against each other with equal/almost equal force, therefore contracting against each other
Ultrasound is vibrations, just like sound is vibrations. Ultrasound travels though the body just like sound would and when it hits something, it bounces back, where it is picked up by a receiver. which then makes an image out of it.
X-rays are electromagnetic waves, like visible light. Other examples of electromagnetic waves are infrared, and ultraviolet. But people cant see infrared nor ultraviolet, even though they are just like visible light. The difference between visible light and all these other kinds of light are just like the difference between red and blue. They are both light but different colors, ultraviolet and infrared are colors we cannot see, and in fact, we can see only a tiny portion of the colors out there. X-rays are just like all these kinds of light and we cant see it but it is able to go through most of the body, bot not bone. Doctors use x-rays to see bones and things like that in the body because x-rays won't pass through bone, but they will go through muscle and skin. So when a doctor takes an x-ray, its just like making a silhouette, but with colors we cant see. Of course, the x-rays make the photo paper change color and that's how we are able to see the image but the principle is the same.
Answer:
0.37sec
Explanation:
Period of oscillation of a simple pendulum of length L is:
T
=
2
π
×
√
(L
/g)
L=length of string 0.54m
g=acceleration due to gravity
T-period
T = 2 x 3.14 x √[0.54/9.8]
T = 1.47sec
An oscillating pendulum, or anything else in nature that involves "simple harmonic" (sinusoidal) motion, spends 1/4 of its period going from zero speed to maximum speed, and another 1/4 going from maximum speed to zero speed again, etc. After four quarter-periods it is back where it started.
The ball will first have V(max) at T/4,
=>V(max) = 1.47/4 = 0.37 sec
