Answer:
Moment about SHOULDER ∑ τ = 3.17 N / m,
Moment respect to ELBOW Στ= 2.80 N m
Explanation:
For this exercise we can use Newton's second law relationships for rotational motion
∑ τ = I α
The moment is requested on the elbow and shoulder at the initial instant, just when the movement begins.
They indicate the angular acceleration, for which we must look for the moments of inertia of the elements involved
The mass of the forearm with the included weight is approximately 2.3 kg, with a length of about 50cm
Moment about SHOULDER
∑ τ = I α
I = I_forearm + I_sphere
the forearm can be approximated as a fixed bar at one end
I_forearm = ⅓ m L²
the moment of inertia of the mass in the hand, let's approach as punctual
I_mass = m L²
we substitute
∑ τ = (⅓ m L² + M L²) α
let's calculate
∑ τ = (⅓ 2.3 0.5² + 0.5 0.5²) 10
∑ τ = 3.17 N / m
Moment with respect to ELBOW
In this case, the arm exerts an upward force (muscle) that is about 3 cm from the elbow
Στ = I α
I = I_ forearm + I_mass
I = ⅓ m (L-0.03)² + M (L-0.03)²
let's calculate
i = ⅓ 2.3 0.47² + 0.5 0.47²
I = 0.2798 Kg m²
Στ = 0.2798 10
Στ= 2.80 N m
a). for velocity, you must have a number, a unit, and a direction.
Yes. This one isn't bad. The 'number' and the 'unit' are the speed.
b). the si units for velocity are miles per hour.
No. That's silly.
'miles' is not an SI unit, and 'miles per hour'
is only a speed, not a velocity.
c). the symbol for velocity is .
You can use any symbol you want for velocity, as long as
you make its meaning very clear, so that everybody knows
what symbol you're using for velocity.
But this choice-c is still wrong, because either it's incomplete,
or else it's using 'space' for velocity, which is a very poor symbol.
d). to calculate velocity, divide the displacement by time.
Yes, that's OK, but you have to remember that the displacement
has a direction, and so does the velocity.
Explanation:
Usually when we think of waves, we think of transverse waves. These are waves where points move up and down perpendicular to the motion of the wave. Examples include water waves, whipping a rope, or even doing the "wave" in a crowd. You can think of these as "two dimensional" waves.
Longitudinal waves are waves where points move left or right, parallel to the motion of the wave. In other words, there is compression and expansion of the medium. Examples include sound waves, or pulses in a slinky.
<span>Chronological essays by the definition of a chronological
meaning in order. There is an order in a specific writing. Like a history write
up from a certain happening years ago. It
is different from procedural essays because these are essays who are giving
instructions of certain set up to guide the person accordingly in doing
something to make it more accurate. Like recipes, instructions in playing, etc.
Example words that are used in chronological essays are first, second, third,
fourth, fifth, next, after, then, lastly, finally, consequently, in addition,
thus, therefore, however, etc.</span>
I think the answer is 2 hope it helps