Question

a 10 kg solid disk of radius 0.5 m is rotated about an axis through its center.the disk accelerates from rest to angular speed of 3.0 rad/s while rotating 2.0 revolutions. what net torque is required? b. if the net torque is applied at an 80 degree angle, what net force was used?​

Answer 1

Answer:

τ ≈ 0.90 N•m

F =

Explanation:

I = ½mR² = ½(10)0.5² = 1.25 kg•m²

α = ω²/2θ = 3.0² / 4π = 0.716... rad/s²

τ = Iα = 1.25(0.716) = 0.8952... ≈ 0.90 N•m

τ = FR

Now we have the unanswered question of reference frame.

80° from what?

If it's 80° from the radial

F = τ/Rsinθ = 0.90/0.5sin80 = 1.818...  ≈ 1.8 N

If it's If it's 80° from the tangential

F = τ/Rcosθ = 0.90/0.5cos80 = 10.311...  ≈ 10 N

There are an infinite number of other potential solutions