Answer:
The mass of the rock is
Explanation:
From the question we are told that
The length of the string is
The angular velocity is
The tension on the string is
Generally the centripetal force acting on the rock is mathematically evaluated as
making m the subject of the formula
substituting values
It's gravitational potential energy at the top will roughly equal it's kinetic energy when it was released (a little is lost to air resistance). Note this will assume the release point is zero potential energy. (we are free to define it that way, just letting you know). Gravitational potential energy is mgh.
mgh=25J
h=25J/(0.5kg x 9.81m/s^2) = 5.097m
So it goes about 5.1 meters above the point where it was released
To what? You did not put the question.
<h2><u>Question</u> :</h2>
When an athlete perspires after running
- Evaporation occurs and helps to cool the body.
- Convection cools the body.
- The body absorbs cold from the surrounding air.
- Heat is conducted away from the body.
<h2><u>Answer</u> :</h2>
When an athlete perspires after running evaporation occurs and helps to cool the body.
Correct option is A.
<h2><u>Explanation</u> :</h2>
When an athlete perspires after running then sweat evaporates and we know that evaporation causes cooling as evaporation requires heat energy. The required heat energy is taken away by the molecules of sweat when they convert from liquid into gas, and this causes cooling on the surface of body. That's why it helps to cool the body.