Answer:

Explanation:
Here we can use energy conservation
As per energy conservation conditions we know that work done by external source is converted into kinetic energy of the disc
Now we have

now we know that work done is product of force and displacement
so here we have


now for moment of inertia of the disc we will have



now from above equation we will have


Answer:

Explanation:
given,
s = 400- 16 t²
we know,
Velocity of an object is defined as the change in displacement per unit change in time.
velocity an also be return as




Hence, instantaneous velocity function given by 
To calculate instantaneous velocity, you need to insert value of time.
ex, instantaneous velocity at t = 4 s
v = -32 x 4 = -128 m/s.
Answer:
v = 0
Explanation:
This problem can be solved by taking into account:
- The equation for the calculation of the period in a spring-masss system
( 1 )
- The equation for the velocity of a simple harmonic motion
( 2 )
where m is the mass of the block, k is the spring constant, A is the amplitude (in this case A = 14 cm) and v is the velocity of the block
Hence

and by reeplacing it in ( 2 ):

In this case for 0.9 s the velocity is zero, that is, the block is in a position with the max displacement from the equilibrium.
The conservation of the mass of fluid through two sections (be they A1 and A2) of a conduit (pipe) or current tube establishes that the mass that enters is equal to the mass that exits. Mathematically the input flow must be the same as the output flow,

The definition of flow is given by

Where
V = Velocity
A = Area
The units of the flow of flow are cubic meters per second, that is to say that if there is a continuity, the volume of input must be the same as that of output, what changes if the sections are modified are the proportions of speed.
In this way


The statement that is a quantitative observation is that bird has four different colors on it (option B).
<h3>What is a quantitative research?</h3>
A quantitative research is a systematic scientific investigation of quantitative properties and phenomena and their relationships, using statistical methods.
A quantitative observation has to do with numbers or numeric analysis.
This suggests that the statement that is a quantitative observation is that bird has four different colors on it.
Learn more about quantitative observations at: brainly.com/question/1434538
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