More circular motion questions (1 Viewer)

[byakuya kuchiki]

Given that a string (0.6m in length), can only sustain a mass of 10kg, find the fastest speed (in rpm) that the string can be rotated (in a horizontal circle) if the mass at the end is 0.2kg?
(*g is specified as 9.8m/s^2)

help is appreciated!!

 

[Trebla]

Given that a string (0.6m in length), can only sustain a mass of 10kg, find the fastest speed (in rpm) that the string can be rotated (in a horizontal circle) if the mass at the end is 0.2kg?
(*g is specified as 9.8m/s^2)

help is appreciated!!

The string can sustain a mass of 10kg vertically which is equivalent to 10 x 9.8 = 98 Newtons
Assuming that the only force acting on the mass is centripetal force:
F = mrω²
Substituting the maximum force it can sustain and the relevant information:
98 = 0.2 x 0.6 x ω²
Solve for ω and convert to relevant units

 

[byakuya kuchiki]

omg thank you thank you. =DD

 

[Lukybear]

The string can sustain a mass of 10kg vertically which is equivalent to 10 x 9.8 = 98 Newtons
Assuming that the only force acting on the mass is centripetal force:
F = mrω²
Substituting the maximum force it can sustain and the relevant information:
98 = 0.2 x 0.6 x ω²
Solve for ω and convert to relevant units

Havent done 4unit circular motion yet, but from physics, i thought centripedal force was F=mv^2/r.

 

[jet]

They're the same thing. v = rω, so substituting in yields the same expression/