A projectile fired upward from the Earth's surface will usually slow down, come momentarily to rest, and return to Earth. For a certain initial speed, however it will move upward forever, with its speed gradually decreasing to zero just as its distance from Earth approaches infinity. The initial speed for this case is called escape velocity. You can find the escape velocity v for the Earth or any other planet from which a projectile might be launched using conservation of energy. The projectile of mass m leaves the surface of the body of mass M and radius R with a kinetic energy Ki = mv²/2 and potential energy Ui = -GMm/R. When the projectile reaches infinity, it has zero potential energy and zero kinetic energy since we are seeking the minimum speed for escape. Thus Uf = 0 and Kf = 0. And from conservation of energy,
Ki + Ui = Kf + Uf
mv²/2 -GMm/R = 0
∴ v = √(2GM/R)
This is the expression for escape velocity.
Answer:
the extension recorded by the student would be smaller than the actual extension of the spring
<span>The longest wavelength within the visible spectrum is the red
light. The answer is letter C. It is called visible light because it is the
only light that can be seen by the human eye. Red light is the longest
wavelength around 620 to 750 nanometer. It is followed by orange which has a
wavelength of 590 t 620 nanometer. And then blue which has a wavelength of 450
to 495 nanometer. And the shortest wavelength is violet which has a wavelength
of 380 to 459 nanometer. </span>
The first one is Force & the second one Power.
