Determine the speed of the stone

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In summary, the conversation is about a person asking for help with two physics questions. The first question involves determining the speed of a stone whirled in a circle with different tensions in the string. The second question involves finding the radius of a rotating cylindrical space station for astronauts to experience half of their Earth weight. The tension in the string is at its maximum when the circle is vertical, and the normal reaction varies with the angle of the astronaut. By setting the angle to 0, the weight registered is half of the Earth weight.
  • #1
hyen84
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Need Help ASAP!

hey can some1 help me with these 2 physics questions..really need it...it's my last homework assigment and i have trouble with this 2...please help it's due tomorrow morning...show what me to do..thankssssssssss

1. A stone is tied to a string (length = 1.27 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the string is nearly parallel to the ground. Next, the circle is vertical. In the vertical case the maximum tension in the string is 15% larger than the tension that exists when the circle is horizontal. Determine the speed of the stone.

2.Suppose the surface (radius = r) of a cylindrical space station is rotating at 33.8 m/s to provide artificial gravity. What must be the value of r for the astronauts to weigh 1/2 of their Earth weight?
 
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1) In the horizontal circular motion case, only the string's tension can provide the required centripetal acceleration.
What forces can provide centripetal acceleration when the circular motion is vertical; in particular, when is the tension of the string at its maximum?
 
  • #3
1. Tension is max at the bottom of the vertical surface and is given by
[tex] T_{max} = W +\frac{mv_{0}^2}{L}[/tex]

2. N is Normal Reaction and it varies as

[tex] N = W\ cos\theta + \frac{mv^2}{L}[/tex]

where \theta is the angle of astronaut with the vertical at any instant

Since its normal rxn is varying with theta , so its weight registered is also varying
so u can solve it for [tex] \theta =0 [/tex] and N= W/2
 

What is the definition of speed?

Speed is a measure of how fast an object is moving. It is usually measured in units of distance per time, such as meters per second or miles per hour.

What is the formula for determining speed?

The formula for speed is distance divided by time, or speed = distance/time. This formula can be used to calculate the average speed of an object.

What is the difference between speed and velocity?

While speed measures how fast an object is moving, velocity also includes direction. This means that two objects can have the same speed but different velocities if they are moving in different directions.

How can speed be measured?

Speed can be measured using various tools such as a speedometer, radar gun, or stopwatch. In some cases, it can also be calculated by measuring the distance an object travels in a given time period.

What factors can affect the speed of an object?

The speed of an object can be affected by factors such as the force applied to it, the weight and size of the object, and the surface it is moving on. Other external factors like air resistance and friction can also impact an object's speed.

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