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3 years ago

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A tetherball is tied to the end of a string of negligible mass. The ball is struck so that it moves in uniform circular motion i

n a horizontal plane, and the string makes an angle of 26° with the vertical pole. The mass of the ball is 1.3 kg. What is the ball's speed

2 answers:

il63 [147K]3 years ago

7 0

The centripetal force is directed parallel to the string and the weight of the ball is always directed downwards. Making a force balance along the direction of vertical axis:
Fc cos 26 = W
where Fc is the centripetal force which is equal to mv2/r
W is the weight which is equal to mg

m v2 /r cos 26= mg
v2 /r cos 26 = g
v2 = rg cos 26
v2 = 2.1(9.81) cos 26
v = 4.30 m/s

The ball's speed is 4.30 m/s.

solmaris [256]3 years ago

4 0

Answer:

v = 24sqrt{r} m/s

Explanation:

as vertical force is equal to weight,

hence W= Fc Cos 26

now , mass= mg

and Fc= mv^{2}/r

where r is the length of string.

putting all the values together in equation 1 :

mg = mv^{2}/r Cos 26

v^{2} = rg Cos 26

v^{2} = r (9.8) Cos 26

v^{2} = 9.8 * (.64691) r

v = 24sqrt{r} m/s

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