Answer:
A. when the mass has a displacement of zero
Explanation:
The velocity of a mass on a spring can be calculated by using the law of conservation of energy. In fact, the total energy of the mass-spring system is equal to the sum of the elastic potential energy (U) of the spring and the kinetic energy (K) of the mass:

where
k is the spring constant
x is the displacement of the mass with respect to the equilibrium position of the spring
m is the mass
v is the velocity of the mass
Since the total energy E must remain constant, we can notice the following:
- When the displacement is zero (x=0), the velocity must be maximum, because U=0 so K is maximum
- When the displacement is maximum, the velocity must be minimum (zero), because U is maximum and K=0
Based on these observations, we can conclude that the velocity of the mass is at its maximum value when the displacement is zero, so the correct option is A.
Answer: 
Explanation:
Given
mass of laptop m=2 kg
The velocity of car u=8 m/s
The coefficient of static friction is 
The coefficient of kinetic friction is 
As the car is moving, so the coefficient of kinetic friction comes into play
deceleration offered by friction 
Using the equation of motion 
insert the values

The answer is,
<u>Farthest from the axis of rotation</u>
Please rate <u>Brainliest</u> (:
Answer:
a) p=0, b) p=0, c) p= ∞
Explanation:
In quantum mechanics the moment operator is given by
p = - i h’ d φ / dx
h’= h / 2π
We apply this equation to the given wave functions
a) φ =
.d φ dx = i k
We replace
p = h’ k
i i = -1
The exponential is a sine and cosine function, so its measured value is zero, so the average moment is zero
p = 0
b) φ = cos kx
p = h’ k sen kx
The average sine function is zero,
p = 0
c) φ =
d φ / dx = -a 2x
.p = i a g ’2x
The average moment is
p = (p₂ + p₁) / 2
p = i a h ’(-∞ + ∞)
p = ∞
1. Frequency is the number of complete waves that pass a point in a second. 2.Wavelength is the distance between two crests or two troughs. 3.Time period <span> is the time it takes for one complete wave to pass a given point. 4. Amplitude is the height of the wave. Hence option 4 is correct. </span>