The second statement is false. The Sun is a star, but not the only star.
Answer:
I would need more electrons 1.3125 10¹⁰ electrons
Explanation:
Static electricity is formed by induced charges in each part of the system, so the net charge does not change.
Let us analyze the situation presented, if the carpet acquires a positive charge, so that it does not alter the total charge in man, it should acquire a negative charge, to have a net negative charge I would need more electrons that have a negative charge.
We can know the number of electrons by a rule of proportions, if an electron has a charge of 1.6 10-19 C for a charge of 2.15 10-9 C how many electrons are needed
# = 2.15 10⁻⁹ /1.6 10⁻¹⁹
# = 1.3125 10¹⁰ electrons
The number is very high for which we will not worry about rounding since the number of electrons must be an integer
The efficiency of steam engine is 26.66 %.
<h3>What is Efficiency?</h3>
The efficiency is defined as the work done by the engine divided by the heat supplied.
Work done is the difference between the heat supplied and heat rejected.
So, efficiency η = (Qs -Qr) / Qs
Given is the heat supplied Qs = 225 Joules and heat rejected Qr =285 . then the work done is
W = 225 -225 = - 60 Joules
Efficiency η = 60/225 x 100%
η = 26.66 %
Thus, the efficiency of the steam engine is 26.66 %.
Learn more about efficiency.
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Answer:
Option A. 39.2 m/s
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 0 m/s
Acceleration due to gravity (g) = 9.8 m/s²
Time (t) = 4 s
Final velocity (v) =?
v = u + gt
Since the initial velocity (u) is 0, the above equation becomes:
v = gt
Thus, inputting the value of g and t, we can obtain the value of v as shown below:
v = 9.8 × 4
v = 39.2 m/s
Therefore, the velocity of the ball at 4 s is 39.2 m/s.
