Newton's law of conservation states that energy of an isolated system remains a constant. It can neither be created nor destroyed but can be transformed from one form to the other.
Implying the above law of conservation of energy in the case of pendulum we can conclude that at the bottom of the swing the entire potential energy gets converted to kinetic energy. Also the potential energy is zero at this point.
Mathematically also potential energy is represented as
Potential energy= mgh
Where m is the mass of the pendulum.
g is the acceleration due to gravity
h is the height from the bottom z the ground.
At the bottom of the swing,the height is zero, hence the potential energy is also zero.
The kinetic energy is represented mathematically as
Kinetic energy= 1/2 mv^2
Where m is the mass of the pendulum
v is the velocity of the pendulum
At the bottom the pendulum has the maximum velocity. Hence the kinetic energy is maximum at the bottom.
Energy can neither be created e destroyed. It can only be transferred from one form to another. Implying this law and the above explainations we conclude that at the bottom of the pendulum,the potential energy=0 and the kinetic energy=294J as the entire potential energy is converted to kinetic energy at the bottom.
1 mA = 0.001 A
Therefore, 5 mA = 0.001 * 5
=0.005 A
Resistance = voltage / current
= 100 / 0.005
= 20000 ohms
Current = voltage / resistance
= 25 / 20000
= 0.00125 A (or) 1.25 mA
Answer: (B) They can be penetrated only with longer wavelengths such as radio and infrared.
Explanation:
A dark nebula is a type of interstellar cloud with such a high density that it "hides" the light of the background stars.
It should be noted that these nebulae are composed mostly of hydrogen (the star's primary fuel), and the absence of light (in the visible range of the electromagnetic spectrum) is caused by the interstellar solid dust that constitutes the cloud, which is why they are also called absorption nebulae.
However, <u>if powerful telescopes that detect at long wavelengths, such as infrared and X-rays, it is possible to observe through these nebulae and even observe the existence of young stars.</u>
