Answer:
They have same density
Explanation:
The density of an object is defined as
where
m is the mass of the object
V is its volume
Let's call and
the mass and the volume of ball C, respectively. Therefore, the density of ball C is:
We know that the volume of ball C is 3 times the volume of ball D, so
And we also know that ball D has 1/3 the mass of ball C:
So, the density of ball D is:
Therefore, the two balls have same density.
Answer:
1. The bird close to the center
2. 4/25 of the original force.
Explanation:
1. Tangential velocity is v=w*d (in m/s), where w is the rotational speed, commonly denoted as the letter omega (in radians per second). d is the distance from the center of the rotating object to the position of where you would like to calculate the velocity (in meters).
As we can note, the furthest from the center we are calculating the velovity the higher it is, because the rotational velocity is not changing but the distance of the object with respect to the center is. If v=w*d, then the lower the d (distance) the lower the tangential velocity.
2. Take a look at the picture:
We have the basic equation for the gravitational force.
We have to forces: Fg1, which is the original force, and Fg2, the force when the mass and the distance changes.
If we consider that mass 2 didn't change (m2'=m2), mass 1 is four times its original (m1'=4*m1) and distance is 5 times the original (r'=5*r), then next step is just plugging it into the equation for Fg2.
Dividing the original force Fg1 by the new force Fg2 (notice you can just as well do the inverse, Fg2 divided by Fg1) gives us the relation between the forces, cancelling all the variables and being left only with a simple fraction!
