A model of a helicopter rotor has four blades, each of length 3.0 m from the central shaft to the blade tip. The model is rotated in a wind tunnel at a rotational speed of 560 rev/min.part A :What is the linear speed of the bladetip?part B :What is the radial acceleration of the bladetip expressed as a multiple of the acceleration of gravity,g?

Respuesta :

Answer with Explanation:

We are given that

r=3 m

Angular frequency=[tex]\omega[/tex]=560rev/min

A.1 revolution=[tex]2\pi[/tex] radian

560 revolutions=[tex]560\times 2\pi[/tex] rad

Angular frequency=[tex]2\times 3.14\times \frac{560}{60}[/tex]rad/s

1 min=60 s

[tex]\pi=3.14[/tex]

Angular frequency=[tex]\omega=58.6rad/s[/tex]

Linear speed=[tex]\omega r[/tex]

Using the formula

Linear speed=[tex]58.6\times 3=175.8m/s[/tex]

Hence, the linear speed of the blade tip=175.8m/s

B.Radial acceleration=[tex]a_{rad}=\frac{v^2}{r}[/tex]

By using the formula

Radial acceleration=[tex]a_{rad}=\frac{(175.8)^2}{3}= 10.301\times 10^3m/s^2[/tex]

Radial acceleration=[tex]\frac{10.301}{9.8}g\times 10^3=1.05\times 10^3 g[/tex]

Where [tex]g=9.8m/s^2[/tex]

Hence, the radial acceleration[tex]=1.05\times 10^3 g[/tex]