Question

A wheel rotates with a constant angular acceleration of 3.50 rad/s2. If the angular speed of the wheel is 2.00 rad/s at t = 0,

Answer 1

Answer:

a) θ = 11 rad, θ = 1.75 rev., b)  w = 9 rad / s, c)  θ = 7.17 rev

Explanation:

This is a rotation kinematics exercise

          θ = θ₀ + w₀ t + ½ α t²

They indicate the initial angular velocity w₀ = 2.00 rad / s, the angular acceleration α = 3.50 rad / s² and that at the initial instant θ₀ = 0

a) let's find the rotated angle

         θ = 0 + 2.00 2.00 +1/2 3.5 2²

         θ = 11 rad

let's reduce 2π rad = 1 rev

        θ = 11 rad (1 rev / 2π rad)

        θ = 1.75 rev.

b) angular velocity

          w = w₀ + α t

          w = 2.00 + 3.50 2

          w = 9 rad / s

c) the angular displacement to reach this speed

          w² = w₀² + 2 α θ

         

in this case they indicate that w = 2  9 = 18 rad / s

          θ = $\frac{w^2 - w_o^2}{2 \alpha }$

          θ = $\frac{18^2 - 2^2 }{2 \ 3.5 }$

          θ = 45.7 rad

let's reduce to rev

          θ = 45.7 rad (1rev / 2π rad)

          θ = 7.17 rev