Answer:
Explanation:
As we know that average angular velocity is defined as the rate of change in angular position in one complete revolution
so it is given as
here we know that seconds hand will complete one revolution in 60 s
so we have angular displacement is given as
so we have
Answer:Anything that has mass is made up of matter – an all-encompassing word for atoms and molecules that make up our physical world. We describe this matter as existing in states (sometimes referred to as phases). Most people are familiar with three states of matter – solids, liquids and gases – but there are two more that are less commonly known but just as important – plasmas and Bose-Einstein condensates.
Explanation:everything has matter
In order to cause electrons to be ejected from the surface of this metal you should use light of a shorter wavelength.
The photoelectric effect is the emission of electrons when electromagnetic radiation, such as light, hits a material. Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics, and solid state and quantum chemistry to draw inferences about the properties of atoms, molecules and solids. The effect has found use in electronic devices specialized for light detection and precisely timed electron emission.
This process is also often referred to as photoemission. In terms of their behaviour and their properties, photoelectrons are no different from other electrons. The prefix, photo-, simply tells us that the electrons have been ejected from a metal surface by incident light.
The photons of a light beam have a characteristic energy, called photon energy, which is proportional to the frequency of the light. In the photoemission process, when an electron within some material absorbs the energy of a photon and acquires more energy than its binding energy, it is likely to be ejected. If the photon energy is too low, the electron is unable to escape the material. Since an increase in the intensity of low-frequency light will only increase the number of low-energy photons, this change in intensity will not create any single photon with enough energy to dislodge an electron. Moreover, the energy of the emitted electrons will not depend on the intensity of the incoming light of a given frequency, but only on the energy of the individual photons.
Learn more about Photoelectric effect here : brainly.com/question/1408276
#SPJ4
Answer:
15.1 N
Explanation:
mass of block (m) = 4 kg
angle of inclination = 36 degrees
applied force (P) = 31 N
acceleration due to gravity (g) = 9.8 m/s^{2}
since the block is moving at a constant speed, it means the acceleration is 0 and therefore the summation of all the forces acting on the body is 0
therefore
P - f - mgsinθ = 0
where
- P = applied force
- f = frictional force
- m = mass
- g = acceleration due to gravity
when P = 31 N and the block is pushed upward
31 - f - (4 x 9.8 x sin 36) = 0
f = 7.96 N
now that we have the value of the frictional force we can find P required to lower the block, our equation becomes p + f - mgsinθ = 0 since the block is to be lowered
P + f - mgsinθ = 0
P = mgsinθ - f
P = (4 x 9.8 x sin 36) - 7.96 = 15.1 N
