Incomplete question.The Complete question is here
A flat uniform circular disk (radius = 2.00 m, mass = 1.00 ✕ 102 kg) is initially stationary. The disk is free to rotate in the horizontal plane about a friction less axis perpendicular to the center of the disk. A 40.0-kg person, standing 1.25 m from the axis, begins to run on the disk in a circular path and has a tangential speed of 2.00 m/s relative to the ground.
a.) Find the resulting angular speed of the disk (in rad/s) and describe the direction of the rotation.
b.) Determine the time it takes for a spot marking the starting point to pass again beneath the runner's feet.
Answer:
(a)ω = 1 rad/s
(b)t = 2.41 s
Explanation:
(a) initial angular momentum = final angular momentum
0 = L for disk + L............... for runner
0 = Iω² - mv²r ...................they're opposite in direction
0 = (MR²/2)(ω²) - mv²r
................where is ω is angular speed which is required in part (a) of question
0 = [(1.00×10²kg)(2.00 m)² / 2](ω²) - (40.0 kg)(2.00 m/s)²(1.25 m)
0=200ω²-200
200=200ω²
ω = 1 rad/s
b.)
lets assume the "starting point" is a point marked on the disk.
The person's angular speed is
v/r = (2.00 m/s) / (1.25 m) = 1.6 rad/s
As the person and the disk are moving in opposite directions, the person will run part of a revolution and the turning disk would complete the whole revolution.
(angle) + (angle disk turns) = 2π
(1.6 rad/s)(t) + ωt = 2π
t[1.6 rad/s + 1 rad/s] = 2π
t = 2.41 s
The position vector can be
transcribed as:
A<span> = 6 i + y j
</span>
i <span>points in the x-direction and j points
in the y-direction.</span>
The magnitude of the
vector is its dot product with itself:
<span>|A|2 = A·A</span>
<span>102 = (6 i +
y j)•(6 i+ y j)
Note that i•j = 0, and i•i = j•j =
1 </span>
<span>100 = 36 + y2
</span>
<span>64 = y2</span>
<span>get the square root of 64 = 8</span>
<span>The vertical component of the vector is 8 cm.</span>
Answer:
Radians
Explanation:
The angular speed is a measure of the rotation speed of a body. It is defined as the angle rotated by a unit of time. Thus, It refers to the angular displacement per unit time and is designated by the Greek letter 
. Its unit in the International System is radian per second (rad / s).
can you have all of them as possibilities ???
Answer:
if one wave has a negative displacement, the displacements would be opposite each other, so the displacement where the waves overlap is less than it would be due to either of the waves separately.
-causes a moment where the net displacement of the medium is zero. energy of waves hasn't vanished, but it is in the form of the kinetic energy of the medium
-then both emerge unchanged
Explanation:
