Answer:
D. the amount of chemical energy equals the amount of heat and light energy.
Explanation:
Given that the first law of thermodynamics affirmed that energy is neither created nor destroyed however, it can be transformed from one form to another. In other words, while, during the transformation of energy, no energy is lost, the input energy is also equal to output energy.
Hence, the chemical energy stored in the log is EQUAL to the heat and light energy produced by burning.
He produced the first orderly arrangement of known elements, he used patterns to predict undiscovered elements
Answer:
E = 124.7 N / C
Explanation:
Let's analyze the exercise: the microwave creates an electromagnetic wave of frequency F = 2.45 GHz, this wave is introduced into the microwave cavity and is reflected on the metal walls, which is why one or more standing waves are formed.
The electric field of the standing wave is
I = E²
E =√I
where I is the intensity of the radiation.
What is it
I = P / A
where P is the effective emission power, almost all the power of the microwave and A is the area of the cavity, in the most used microwaves
P = 700 W and the area is A = 25 x 18 cm² = 0.045 m²
I = 700 / 0.045
I = 15555.56 W/m²
let's calculate the electric field
E = √15555.56
E = 124.7 N / C
Answer:
59.18 kg
Explanation:
use f=ma
f= 580 N
a = 9.8 m/s 2
weigh(m) doesn't change only force(F) changes
Answer:
Calculating Coefficient of friction is 0.229.
Force is 4.5 N that keep the block moving at a constant speed.
Explanation:
We know that speed expression is as
.
Where,
is initial speed, V is final speed, ∆s displacement and a acceleration.
Given that,
=3 m/s, V = 0 m/s, and ∆s = 2 m
Substitute the values in the above formula,

0 = 9 - 4a
4a = 9

is the acceleration.
Calculating Coefficient of friction:


Compare the above equation

Cancel "m" common term in both L.H.S and R.H.S





Hence coefficient of friction is 0.229.
calculating force:


F = 4.5 N
Therefore, the force would be <u>4.5 N</u> to keep the block moving at a constant speed across the floor.