Answer:
(a) k =
(b) τ =
∝
Explanation:
The moment of parallel pipe rotating about it's axis is given by the formula;
I =
---------------------------------1
(a) The kinetic energy of a parallel pipe is also given as;
k =
--------------------------------2
Putting equation 1 into equation 2, we have;
k = 
k =
(b) The angular momentum is given by the formula;
τ = Iw -----------------------3
Putting equation 1 into equation 3, we have
τ = 
But
τ = dτ/dt =
------------------4
where
dw/dt = angular acceleration =∝
Equation 4 becomes;
τ =
∝
B.
The child is too old to be gaining something from the screen time.
I attached the missing picture.
We can figure this one out using the law of conservation of energy.
At point A the car would have potential energy and kinetic energy.

Then, while the car is traveling down the track it loses some of its initial energy due to friction:

So, we know that the car is approaching the point B with the following amount of energy:

The law of conservation of energy tells us that this energy must the same as the energy at point B.
The energy at point B is the sum of car's kinetic and potential energy:

As said before this energy must be the same as the energy of a car approaching the loop:

Now we solve the equation for

:
We are given: Final velocity (
)=20 m/s .
Time t= 2.51 s and
distance s = 82.9 m.
We know, equation of motion

Let us plug values of final velocity, and time in above equation.


Subtracting 2.51a from both sides, we get
-----------equation(1)
Using another equation of motion

Plugging values of vi =20-2.51a, t=2.51 and distnace s=82.9 in this equation.
We get,

Now, we need to solve it for a.
20-20+2.51a=165.8a.
-163.29a=0
a=0.
So, the acceleration would be 0 m/s^2.
Answer:
Mass
Explanation:
Inertia is essentially an object's tendency to stay in motion or at rest unless it is forced to do otherwise (pun intended). It only makes sense to me that mass would best quantify an object's inertia, because an object with more mass would be harder to move and/or stop from moving.