Answer:
A force has both magnitude and direction, therefore: Force is a vector quantity; its units are newtons, N. Forces can cause motion; alternatively forces can act to keep (an) object(s) at rest. ... Consider two forces of magnitudes 5 N and 7 N acting on a particle, with an angle of 90◦ between them.
Explanation:
from google
These are the Kepler's laws of planetary motion.
This law relates a planet's orbital period and its average distance to the Sun. - Third law of Kepler.
The orbits of planets are ellipses with the Sun at one focus. - First law of Kepler.
The speed of a planet varies, such that a planet sweeps out an equal area in equal time frames. - Second law of Kepler.
Wavelength= velocity/frequency
5/2.5=2
Answer:
3.066×10^21 photons/(s.m^2)
Explanation:
The power per area is:
Power/A = (# of photons /t /A)×(energy / photon)
E/photons = h×c/(λ)
photons /t /A = (Power/A)×λ /(h×c)
photons /t /A = (P/A)×λ/(hc)
photons /t /A = (680)×(678×10^-9)/(6.63×10^-34)×(3×10^-8)
= 3.066×10^21
Therefore, the number of photons per second per square meter 3.066×10^21 photons/(s.m^2).
