Electromagnetic Waves:
Radio waves, television waves, and microwaves.
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
Explanation:
It is known that;
Now, we need to calculate the value of L, that is, angular momentum.
Therefore,
L= mvr
where, m = mass
v = velocity
r = radius
Hence,
L = 
So,
L = 
= 10.37 Js
Thus, we can conclude that angular momentum of the rod and clay system about the point of support immediately after the inelastic collision is 10.37 Js.
Answer:
t = 26.39 s
Explanation:
given,
Length of runway = 1.60 mi = 8448 ft
acceleration of the jet = 10.1 ft/s²
deceleration of the jet = 7.21 ft/s²
Let x be the distance of no return
using equation of motion
v² = u² + 2 a s
v² = 0 + 2 × 10.1 × x
v = √(20.2 x)
now, after reaching that Point the deceleration of the plane start
using equation of motion
final velocity of the first case will be the initial velocity of the second case
v² = u² + 2 a s
0 = 20.2 x - 2 x 7.21 x(8448-x)
34.62 x = 121820.16
x = 3518.78 ft
time taken to reach no return point
t² = 696.788
t = 26.39 s
time taken to reach the no return point is equal to 26.39 s.
Answer:
Explanation:
Conservation of momentum is used to solve
Unfortunately we have a missing piece of information such as the initial velocity of the unknown mass train.
If we ASSUME that the second train is at rest
5000(100) + m(0) = 5000(50) + m(50)
which means m = 5000 kg
However, I'll show you the importance of knowing that initial velocity by finding it assuming the other answers are valid
if m = 15000 kg
5000(100) + 15000(v₀) = (5000 + 15000)(50)
v₀ = 33 ⅓ m/s
if m = 10000 kg
5000(100) + 10000(v₀) = (5000 + 10000)(50)
v₀ = 25 m/s
if m = 8000 kg
5000(100) + 8000(v₀) = (5000 + 8000)(50)
v₀ = 18.75 m/s
So you can see why I had to assume an initial velocity. Any of the masses could work if the initial velocity is chosen correctly.
