Answer:
A friend snorkeling just below the surface of the water along the same shore will detect the sound first.
Explanation:
- The speed of sound in water medium is faster than that through the air.
- Sound propagates through the medium by transferring through the molecules on it. Water has more closely packed molecules due to which the speed is faster.
- In fact, the sound's speed in water is almost four times faster than that in the air.
- So the guy in the water surface gets to hear sound faster than the one in sore.
Answer: BOTH ARE TRUE
Explanation: Nondestructive testing or Evaluation is a term used in the field of science and technology to describe the evaluations, analysis or testing carried out on components of materials without destroying any part or components of the test materials. It is very useful in scientific research or industrial engineering environments. When any disruption of physical structure or configuration of a component will lead to discontinuing of the test, and it may not affect the usefulness of the affected parts.
Answer:
1.65
Explanation:
The equation of the forces along the horizontal direction is:
(1)
where
F = 65 N is the force applied with the push
is the frictional force
m = 4 kg is the mass
is the acceleration
The force of friction can be written as
(2), where
is the coefficient of kinetic friction
R is the normal force exerted by the floor
The equation of forces along the vertical direction is
(3)
since the bookcase is in equilibrium. Substituting (2) and (3) into (1), we find

And solving for
,

Answer:
The correct option is;
A. The potential energy between both like charges and like poles increases as they move closer together
Explanation:
Here we have that when we move the like poles of two bar magnets close to each other, there is an increased resistance in the continuing motion, therefore for each extra gap closer achieved, there is an increase in potential energy
Similarly, when two like charges are brought closer together, the potential energy, or the energy available to push the two like charges apart increases charge as the as the charges are brought closer together
Therefore, the correct option is the potential energy between both like charges and like poles increases as they move closer together.
R = ρ L/A. R= resistance, ρ= resistivity, L= length of the conductor. A = area of the conductor. Resistance is directly proportional to the length of the conductor. So if length of the conductor is decreased, resistance will also decrease. Hence A is the correct option