Motion of a ball thrown by a person upwards and caught after some time is an example of motion in which displacement of the particle is zero but acceleration is not zero in journey.
The displacement of the ball is zero because the starting and end point of the motion are same, i.e, the person's hands.During its motion, the acceleration of ball is constant and non zero called as acceleration due to gravity, g= -9.8 m/s². The velocity of ball is continuously changing. It first decreases during the upward motion of the ball and then increases during the downward journey.The acceleration remains constant and non zero all the time.
Easy !
Take any musical instrument with strings ... a violin, a guitar, etc.
The length of the vibrating part of the strings doesn't change ...
it's the distance from the 'bridge' to the 'nut'.
Pluck any string. Then, slightly twist the tuning peg for that string,
and pluck the string again.
Twisting the peg only changed the string's tension; the length
couldn't change.
-- If you twisted the peg in the direction that made the string slightly
tighter, then your second pluck had a higher pitch than your first one.
-- If you twisted the peg in the direction that made the string slightly
looser, then your second pluck had a lower pitch than the first one.
Answer: Black hole.
Explanation:
As the massive star "compacts" under its own gravity, it triggers a massive supernova, after this point the remains of the star can become a neutron star, which is a very compact star made primarily, as the name says, of neutrons. The other possibility is a black hole, which is a finite region of space wherein it's interior there is a big concentration of mass, which creates a gravitational field strong enough that there is no particle that can escape it.
An element called Silica.
