When will an object dropped from rest attain a speed of 30 m/s?
1 answer:
<h3><u>Answer</u> :</h3>
Initial velocity = zero (i.e., free fall)
Final velocity = 30m/s
Acceleration due to gravity = 10m/s²
For a body falling freely under the action of gravity, g is taken positive
◈ <u>First equation of kinenatics</u> :
⇒ v = u + gt
⇒ 30 = 0 + 10t
⇒ t = 30/10
⇒ <u>t = 3s</u>
Hence, object will attain a speed of 30m/s after 3s.
You might be interested in
Answer:
explanation of this effect is the photoelectric effect
Explanation:
Let's describe the process, when light of large wavelength falls, this implies a small energy, according to Planck's equation
E = h f =
the energy of the photons is not enough to carry out an electronic transition between two states of the material, when we decrease the wavelength (the energy of the photons increases), the point is reached where the energy of the beam is equal to some energy of a transition, by which the electrons are promoted and since we can see a certain charge, as the atoms are neutral, some electrons must be removed from the material, this is represented in the macroscopic case as the work function of the material, consequently a unbalanced load that is what we can measure.
When we increase the lightning intensity, what we do is that we increase the number of photons and if each photon can remove an electron, by removing the electrons the difference between it and the positive charge (fixed in the nuclei) increases.
We can analyze the interaction of the photon and the electron as a particular collision.
The explanation of this effect was made by Einstein in his explained of the photoelectric effect