Answer:

Explanation:
We use the following rotational kinematic equation to calculate the angular acceleration of the rod:

Here
is the final angular speed,
is the initial angular speed and
is the angular acceleration. The rod starts rotating from rest (
):

Recall that the angular speed is defined in function of the tangential speed (v) and the radius (r) of the circular motion:

In this case the radius is given by
. Replacing (2) in (1):

Answer:
The speed of elephant must be 1.4 m/s.
Explanation:
Mass of the elephant, M = 2800 kg
Mass of sprinter, m = 77 kg
Speed of sprinter, v = 8.5 m/s
It is required to find the speed of elephant to have the same kinetic energy as that of sprinter. So,

So, the speed of elephant must be 1.4 m/s.
Answer:
If an object has a high density then the molicules making up that object are closly packed togeather. Because of this, objects with a higher density will have more mass than objects of the same size that have a lesser density.
The number of protons always equals the number of neutrons in all isotopes: false
Different isotopes for the same element always have the same number of protons: True
The number of protons never equals the number of neutrons in an isotope: False (example: He)
Different isotopes for the same element will always have the same numbers of neutrons: false
Answer:
The extension is directly proportional to the force applied.
ex: if the force is doubled, the extension doubles. This works until the limit of proportionality is exceeded.
Hope this helped~
Explanation: