Answer:
B. It begins to rotate counterclockwise
Explanation:
It can happen that the merry-go-round remains at rest in the case when the person is standing on the axle of the merry go round whose axis is fixed to some rigid support, but here the person is standing at the center of the merry-go-round not at the axle hence the according to the conservation of angular momentum. Angular momentum is given as:
for the conservation of momentum
where:
moment of inertia of the merry-go-round
angular velocity of the merry-go-round
moment of inertia of the bicycle wheel
angular velocity of the wheel
As the person tries to stop the wheel which is rotating then the person feels an opposing force which tries to moves the whole system in its direction.
Answer:
The radius r of the metal sphere.
Explanation:
From Gauss's law we know that for a spherical charge distribution with charge 
, the electrical field at distance 
from the center of the sphere is given by
What is important to notice here is that the radius of the sphere does not matter because any test charge sitting at distance feels the force as if all the charge were sitting at the center of the sphere.
This situation is analogous to the gravitational field. When calculating gravitational force due to a body like the sun or the earth, we take not of only the mass of the sun and the distance from it's center; the sun's radius does not matter because we assume all of its mass to be concentrated at the center.
Answer:
After 1 half-life (500 years), 500 g of the parent isotope will remain. After 2 half-lives (1000 years), 250 g of the parent isotope will remain. After 3 half-lives (1500 years), 125 g of the parent isotope will remain. After 4 half-lives (2000 years), 62.5 g of the parent isotope will remain.
Explanation:
