College Physics
posted by Taylor
A 0.35 kg stone attached to a 0.8 m long string is rotated in a horizontal plane. The string makes an angle of 20° with the horizontal. Determine the speed of the stone.
I've tried tan 20= gr/v^2 = (9.8)(.8)/v^2 = 4.7 m/s and that's not the correct answer (online homework). Any help or explanation would be appreciated

Elena
mg=Tsin α
mv²/R=Tcos α
mgR/ mv² = Tsin α/Tcos α
gR/ v² =tan α
gLcos α/ v² =tan α
v=sqrt{ gLcos α/ tan α} =sqrt{9.8•0.8•cos20°/tan20°} = 4.5 m/s
Respond to this Question
Similar Questions

college physics
A stone with a mass of 0.800 is attached to one end of a string 0.800 long. The string will break if its tension exceeds 60.0 . The stone is whirled in a horizontal circle on a frictionless tabletop; the other end of the string remains … 
Physics
A boy is whirling around a stone tied at the end of a 0.71 m long string at constant angular speed of 4 revolutions per second in a plane perpendicular to the ground. The string breaks when it is making an angle of 54 degrees above … 
PHYSICS
A boy is whirling around a stone tied at the end of a 0.55 m long string at constant angular speed of 5 revolutions per second in a plane perpendicular to the ground. The string breaks when it is making an angle of 53 degrees above … 
physics
A stone tied to the end of a string, 80 cm long, is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 25 seconds what is the magnitude and direction of the acceleration of the stone? 
Physics
A 0.30 kg stone attached to a 0.8 m long string is rotated in a horizontal plane. The string makes an angle of 15° with the horizontal. Determine the speed of the stone. 
physics
A stone is tied to a string (length = 1.05 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. … 
physics
a stone with a mass of .700kg is attached to the end of a rting 0.900m long. the string will break if its tension exceed 60.0 N. the stone is whirled in a horizontal circle on a frictionless tabletop; the other of the string remain … 
physics
A stone is tied to a string (length = 1.25 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. … 
college physics 1
Reviewing Interactive Solution 5.46 will help in solving this problem. A stone is tied to a string (length = 1.29 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the … 
Physics
A stone with mass 0.8kg is attached to one end of a string 0.9m long . The string will break if its tension exceeds 600N. The stone is whirled in a horizontal circle ,the other end of the string remains fixed. Find the maximum speed …