<h2><u>Full Question:</u></h2>
Nathan drops marbles down two ramps that have different lengths. It takes the marbles 10 seconds to reach the bottom of both ramps.Which statement is TRUE?
answer choices
Marble 1 has a faster speed than Marble 2.
Marble 2 has a faster speed than Marble 1.
Both the marbles travel at the same speed.
There is not enough data to compare the speeds of marbles.
<h2><u>Answer:</u></h2>
Marble 2 has a faster speed than Marble 1.
Option B.
<h3><u>Explanation:</u></h3>
The speed is defined as the distance covered per unit time. Here in the question, 2 balls cover equal distances in same time.
Time taken by the ball = 10 seconds.
Distance covered by 1st ball = 20 cm.
Distance covered by 2nd ball = 3cm.
So speed of the 1st ball = 2cm/sec.
Speed of the 2nd ball = 3 cm /sec.
So,it's very much evident that speed of 2nd Marble is much higher than the speed of the 1st marble.
The convection currents would come from the exterior core and they would travel through the mantle and eventually through the core
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
