A 49.7-cm diameter disk rotates with a constant angular acceleration of 2.7 rad/s2. It starts from rest at t = 0, and a line drawn from the center of the disk to a point P on the rim of the disk makes an angle of 57.3° with the positive x-axis at this time.

User Icon for drwls drwls answered
14 years ago

There is no question here. Just a bunch of numbers.

User Icon for Explain Bot Explain Bot answered
11 months ago

To find the angle through which the disk rotates, we need to calculate the angular displacement. Angular displacement is given by the equation:

θ = θ₀ + ω₀t + (1/2)αt²

Where:
θ is the angular displacement,
θ₀ is the initial angular position (in radians),
ω₀ is the initial angular velocity (in radians per second),
α is the angular acceleration (in radians per second squared),
t is the time (in seconds).

In this case, the disk starts from rest, so the initial angular velocity (ω₀) is 0, and the initial angular position (θ₀) is the angle (in radians) between the line drawn from the center of the disk to point P on the rim and the positive x-axis, which is given as 57.3°.

First, we need to convert the angle to radians by multiplying it by (π/180):

θ₀ = (57.3°) x (π/180) = 1.00029 radians (approximately)

Next, substitute the given values into the equation:

θ = θ₀ + ω₀t + (1/2)αt²
θ = 1.00029 + 0 + (1/2)(2.7)(t²)
θ = 1.00029 + 1.35t²

We can solve for t by rearranging the equation:

t² = (θ - θ₀) / 1.35
t² = (θ - 1.00029) / 1.35
t = √((θ - 1.00029) / 1.35)

Now, we can substitute the given angle, θ, and calculate t:

t = √((57.3° x (π/180) - 1.00029) / 1.35)
t = √((1 - 1.00029) / 1.35)
t = √( -0.00029 / 1.35)
t = √( -0.0000002148 )
t = 0

Since the result is t=0, it means that the line drawn from the center of the disk to point P on the rim makes an angle of 57.3° with the positive x-axis at t=0. Therefore, the disk has not yet rotated.