Answer:
C. Mass is independent of the force acting on the mass.
Weight depends on the gravitational force acting on the mass.
Example: A mass of 1 kg on the earth still has a mass of 1 kg on the moon;
whereas the weight of that mass on earth is 9.8 N and only 1/6 of that amount on the moon.
To solve this problem we will apply the concept of frequency in a string from the nodes, the tension, the linear density and the length of the string, that is,

Here
n = Number of node
T = Tension
= Linear density
L = Length
Replacing the values in the frequency and value of n is one for fundamental overtone



Similarly plug in 2 for n for first overtone and determine the value of frequency



Similarly plug in 3 for n for first overtone and determine the value of frequency



The question is about unclear since no picture provided. But from the question, it could be guessed that the box is moving back and forth on the frictionless plane at the amplitude of A in simple harmonic motion.
Answer:
D. At x=0, it's acceleration is at a maximum
Explanation:
As the box move forward, it reaches point A and than move backward. Theoretically, the box will move backwards, through its origin, to point -A and then going forward.
Point A is the maximum displacement of the box in this case. At this point, the box instantaneously stop to go backward. Therefore the velocity at that moment is zero.
From point -A, the box travel forward and keep building up speed due to the release in potential energy of the spring. And at point x=0, the velocity become maximum. After point x=0, the velocity of the box slows down due to the conversion of kinetic energy to potential energy of the spring. And as it reaches point A, it reaches zero velocity.
The same can be said as the box travels backward from point A to -A
Answer:

Explanation:
= Velocity of one lump = 
= Velocity of the other lump = 
m = Mass of each lump = 
The collision is perfectly inelastic as the lumps stick to each other so we have the relation

The velocity of the stuck-together lump just after the collision is
.
Answer:
b is the answer
Explanation:
tq friend b is the answer