<span>We can use the equation for the force of gravity to solve this question.
F = G M1 M2 / R^2
Let R be the radius of the planet.
f0 = G M1 M2 / (2R)^2
f0 = (1/4) x (G M1 M2 / R^2)
We can find an expression for f2.
f2 = G M1 M2 / (4R)^2
f2 = (1/16) x (G M1 M2 / R^2)
We can express f2 in terms of f0:
f2 = (4/16) x f0
f2 = 0.25 f0</span>
Hi!
The energy of the block is 4 m/s
To calculate this, you need to use the equation for
kinetic energy. The block is sliding (i.e. it's moving). If the object is sliding across a level surface, the only energy it has is kinetic energy, because
there is no change in potential energy (which changes with height). So, the mechanical energy will be pure kinetic energy. The equation is the following, derived from the expression for kinetic energy:

Have a nice day!
"Frequency" is a measure of how frequent something is.
Its unit is the "Hertz".
1 Hertz = 1 per second
Answer:
This is an incomplete question. The complete question is --
An individual white LED (light-emitting diode) has an efficiency of 20% and uses 1.0 W of electric power.
How many LEDs must be combined into one light source to give a total of 3.8W of visible-light output (comparable to the light output of a 100W incandescent bulb)?
And the answer is --
19 LEDs
Explanation:
The full form of LED is Light emitting diode.
It is given that the efficiency of the LED bulb is 20 %
1 LED uses power = 1 W
So the output power of 1 LED = 0.2 W
We need to find the power required to give a 3.8 W light.
Power required for 3.8 W = Number of LEDs required = (total required power / power required for 1 LED )
= 3.8 / 0.2
= 19
Therefore, the number of LEDs required is 19.