Answer:
<em>B. 68.6m</em>
Explanation:
<u>Free Fall Motion
</u>
When a body is left to move in the air with no friction, the motion is ruled only by the force of gravity. The vertical distance a body travels in the air after a time t is
.

We know the egg takes 3.74 seconds to reach the ground. The height it was launched from is


The closest correct option is
B. 68.6m
Answer:
when the direction of the Current changes.
Explanation:
Electromagnet refers to an iron ore wrapped around with a coil of wire, in presence of electric current. As it acts like a magnet, when current is passed through it.
The north & south poles of magnetic fields produced by such magnet, change with direction of current passed through it.
Answer:

Explanation:
To solve this exercise it is necessary to take into account the concepts related to gravitational potential energy, as well as the concept of perigee and apogee of a celestial body.
By conservation of energy we know that,

Where,

Replacing


Our values are given by,





Replacing at the equation,


Therefore the Energy necessary for Sputnik I as it moved from apogee to perigee was 
Answer: D
Wavelength λ = 7.5 × 10^-11 m
Explanation:
You are given the frequency of an electromagnetic wave to be:
F = 4.0 x 1018 Hz. And the speed of light C to be
C = 3 × 10^8 m/s
From wave speed formula:
Wave speed is the product of waves frequency and wavelength. That is,
V = fλ
Where
f = frequency
λ = wavelength
V = C = speed of light
Substitute the values of the parameters into the formula
C = fλ
3 × 10^8 = 4 × 10^18 × λ
Make λ the subject of formula
λ = (3×10^8)/(4×10^18)
λ = 7.5 × 10^-11 m
Therefore, the wavelength of the wave is 7.5 × 10^-11 m