Your your answers are a and c hope this helps
Answer:
284 m
Explanation:
According to engineeringtoolbox(dot)com the speed of compressive sound in concrete is 3700 m/s
The speed of sound in standard air is 343 m/s
If t is the time in seconds of sound travel through the concrete and d is the distance
d = 3700t
d = 343(t + 0.75)
3700t = 343t + 257
3,357t = 257
t = 0.07663 s
d = 3700(0.07663) = 284 m
d = 343(0.07663 + 0.75) = 284 m
Answer:
B) electrons
Explanation:
When charge is transferred by friction, induction or conduction, the charge carriers are the electrons.
In fact, protons and neutrons are found within the nucleus of the atoms, so they are tightly bound and they cannot be easily gained/given off. On the contrary, electrons are found in the electron clouds around the nucleus, so atoms can more easily gain/lose electrons, which become free and can be passed by an object to another.
The three methods of charging are:
- Friction: by rubbing two objects together, electrons may be transferred from one to another
- Induction: by moving a charged object closer to a neutral object, opposite charges in the neutral object migrate towards the opposite ends of the object, and if the object is connected to the ground, the charges of one polarity leave the object, leaving the object charged
- Conduction: by putting a charged object in contact with a neutral object, electrons can be transferred from the charged object to the neutral one
Answer:
<em>P = 1500 Watt</em>
Explanation:
<u>Mechanical Work and Power
</u>
Mechanical work is the amount of energy transferred by a force.
Being F the magnitude of the force vector and s the distance, the work is calculated as:
W=F.s
Power is the amount of energy transferred or converted per unit of time. In the SI, the unit of power is the watt, equal to one joule per second.
The power can be calculated as:
Where W is the work and t is the time.
The force to be considered is the weight of the mass of m=100 kg, :
F = 100 * 10 = 1000 N
The distance is s=3 m, thus the work done by the weight lifter is:
W = 1000 N * 3 m
W = 3000 J
Finally, the power is:
P = 1500 Watt