Answer:
B) Power is the rate at which work is done
Missing question:
"Determine (a) the astronaut’s orbital speed v and (b) the period of the orbit"
Solution
part a) The center of the orbit of the third astronaut is located at the center of the moon. This means that the radius of the orbit is the sum of the Moon's radius r0 and the altitude (
) of the orbit:
This is a circular motion, where the centripetal acceleration is equal to the gravitational acceleration g at this altitude. The problem says that at this altitude,
. So we can write
where
is the centripetal acceleration and v is the speed of the astronaut. Re-arranging it we can find v:
part b) The orbit has a circumference of
, and the astronaut is covering it at a speed equal to v. Therefore, the period of the orbit is
So, the period of the orbit is 2.45 hours.
Answer: B: It can be made out of wire
Explanation: i just had this question and put this answer and gotten it right:)
To solve this problem we will use the trigonometric concepts to find the distance h, which will allow us to find the speed of Jeff and that will finally be the variable that will indicate the total tension, since it is the variable of the centrifugal Force given in the vine at the lowest poing of the swing.
From the image:
When Jeff reaches his lowest point his potential energy is converted to kinetic energy
Tension in the string at the lowest point is sum of weight of Jeff and the his centripetal force
Therefore the tension in the vine at the lowest point of the swing is 842.49N