Answer:
"h" signifies Planck's constant
Explanation:
In the equation energy E = h X v
The "h" there signifies Planck's constant
Planck's constant is a value, that shows the rate at which the energy of a photon increases/decreases, as the frequency of its electromagnetic wave changes.
It was named after Max Planck who discovered this unique relationship between the energy of a light wave and its frequency.
Planck's constant, "h" is usually expressed in Joules second
Planck's constant = 
The speed
of the elevator at the beginning of the 8 m descent is nearly 4 m/s. Hence, option A is the correct answer.
We are given that-
the mass of the elevator (m) = 1000 kg ;
the distance the elevator decelerated to be y = 8m ;
the tension is T = 11000 N;
let us determine the acceleration 'a' by using Newton's second law of motion.
∑Fy = ma
W - T = ma
(1000kg x 9.8 m/s² ) - 11000N = 1000 kg x a
9800 - 11000 = 1000
a = - 1.2 m/s²
Using the equation of kinematics to determine the initial velocity.
² =
² + 2ay
= √ ( 2 x 1.2m/s² x 8 m )
= √19.2 m²/s²
= 4.38 m/s ≈ 4 m/s
Hence, the initial velocity of the elevator is 4m/s.
Read more about the Equation of kinematics:
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Answer:
The spring was compressed the following amount:

Explanation:
Use conservation of energy between initial and final state, considering that the surface id frictionless, and there is no loss in thermal energy due to friction. the total initial energy is the potential energy of the compressed spring (by an amount
), and the total final energy is the addition of the kinetic energies of both masses:



To solve this problem we will apply the kinematic equations of linear motion and centripetal motion. For this purpose we will be guided by the definitions of centripetal acceleration to relate it to the tangential velocity. With these equations we will also relate the linear velocity for which we will find the points determined by the statement. Our values are given as


PART A )


Calculate the velocity of the motorcycle when the net acceleration of the motorcycle is 




Now calculate the angular velocity of the motorcycle



Calculate the angular acceleration of the motorcycle



Calculate the time needed by the motorcycle to reach an acceleration of




PART B) Calculate the velocity of the motorcycle when the net acceleration of the motorcycle is 




PART C)
Calculate the radial acceleration of the motorcycle when the velocity of the motorcycle is 



Calculate the net acceleration of the motorcycle when the velocity of the motorcycle is 



PART D) Calculate the maximum constant speed of the motorcycle when the maximum acceleration of the motorcycle is 




Answer:
the answer the correct one is c
Explanation:
Electric charges of different signs attract and those of the same sign repel. In addition, there are two types of insulating bodies, where the loads are fixed (immobile) and metallic (with mobile loads.
Let's analyze the situation presented
* A rod with positive approaches and the sphere is attracted, so the charge on the sphere is negative
* A rod with a negative charge approaches and the sphere is attracted, therefore the charge of the sphere must be positive.
For this to happen, the sphere must be unloaded and the charge that creates the phenomenon are induced charges because the mobile charges of the same sign as the sphere are repelled.
when checking the answer the correct one is c