Answer:
Friction force always acts tangent to the surface at points of contact. Friction force acts opposite to the direction of motion.
Explanation:
Answer:
Current I = Q / t = 5.0E-6 coulomb/.02 sec = 2.5E-4 amps
I = .00025 amps
The average velocity of the following 4 velocity measurements will be d) 8.7 m/s
average of given velocities = sum of all velocities divided by number of velocity mentioned in the question
average velocity = ( v1 + v2 + v3 + v4 ) / 4
= ( 9.6 + 8.8 + 7.6 + 8.7 ) / 4 = 8.675 ≈ 8.7 m/s
correct answer d)
The average velocity of the following 4 velocity measurements will be d) 8.7 m/s
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Answer: 363 Ω.
Explanation:
In a series AC circuit excited by a sinusoidal voltage source, the magnitude of the impedance is found to be as follows:
Z = √((R^2 )+〖(XL-XC)〗^2) (1)
In order to find the values for the inductive and capacitive reactances, as they depend on the frequency, we need first to find the voltage source frequency.
We are told that it has been set to 5.6 times the resonance frequency.
At resonance, the inductive and capacitive reactances are equal each other in magnitude, so from this relationship, we can find out the resonance frequency fo as follows:
fo = 1/2π√LC = 286 Hz
So, we find f to be as follows:
f = 1,600 Hz
Replacing in the value of XL and Xc in (1), we can find the magnitude of the impedance Z at this frequency, as follows:
Z = 363 Ω
<h2>
Answer: C. Kinetic energy</h2>
Explanation:
Heat is energy in transit, in fact it is a transfer of thermal energy from one body to another.
So, when a metal is heated is because we have two bodies with different temperatures and thermal energy is transferred from one body to another, implying a high speed and kinetic energy in the particles involved (electrons in this case).
This is because the kinetic energy of a particle is that energy it possesses due to its movement, and according to the first principle of thermodynamics, there is a relationship between heat and movement, since the metal is composed of particles that are in motion (to a certain extent).
In this way, with the increase of the temperature of the metal, there is an increase of the kinetic energy of its free electrons with a gain of velocity (movement), therefore a gain in kinetic energy.