I have no idea what that is, but all of your answers right
Answer:
Explanation:
f
=
v
λ
where v is the velocity of the wave
λ
is the wavelength.
Answer:
here 20 lb object will hit the ground first
Explanation:
Acceleration of the object while it is dropped in air is given as



so acceleration of the object is independent of the mass of the object
now time to reach the ground is given as


for 20 pound object


for 50 pound object


Answer:

Explanation:
Since there's no external force beside gravity acting on the rod, we can use the law of energy conservation to calculate for the speed of rod center of gravity before hitting the surface.
Also as the rod is uniform and this, its center of gravity is at distance h/2 from the surface.




This is because metal is a conductor of electricity while rubber is not (rubber is an insulator). Therefore the metal is more amenable to 'ground' the high charge in the lightning than rubber would. This is also why, when lightning strikes metal, it is safely 'grounded' while if it strikes a non-conductor, most occasionally, it explodes into a fire.