Question

A regulation basketball has a 14 cm diameter and may be approximated as a thin spherical shell.
How long will it take a basketball starting from rest to roll without slipping 2.8 m down an incline that makes an angle of 41.1° with the horizontal? The acceleration of gravity is 9.81 m/52
Answer in units of s.

Answers

There are no human answers yet.
Answered by GPT 3.5
To solve this problem, we'll use the concept of rotational motion.

First, let's find the mass of the basketball. The volume of a sphere is given by V = (4/3)πr^3, where r is the radius. The diameter of the basketball is 14 cm, so the radius is 7 cm = 0.07 m. Plugging this into the volume formula, we get:

V = (4/3)π(0.07)^3 = 0.015292 m^3

The density of a basketball is about 600 kg/m^3, so the mass of the basketball is:

m = density * volume = 600 kg/m^3 * 0.015292 m^3 = 9.1752 kg

Now, let's find the moment of inertia of the basketball. The moment of inertia I for a thin spherical shell is given by I = (2/3)mr^2, where m is the mass and r is the radius. Plugging in the values, we get:

I = (2/3) * 9.1752 kg * (0.07 m)^2 = 0.0467 kg⋅m^2

Next, we'll use the torque equation τ = Iα to relate the angular acceleration α with the applied torque τ. Since the basketball is assumed to roll without slipping, α and a (linear acceleration) are related by α = a/r, where r is the radius. Plugging in the values, we get:

τ = I * (a/r) = (2/3) * 9.1752 kg * (0.07 m)^2 * (a/0.07 m) = 0.0975 a kg⋅m^2

When the basketball starts rolling without slipping, the torque acting on it is due to the component of the gravitational force along the incline, which is mgsin(θ), where g is the acceleration due to gravity and θ is the angle of the incline. Plugging in the values, we get:

τ = mgsin(θ) = 9.1752 kg * 9.81 m/s^2 * sin(41.1°) = 58.2587 N⋅m

Setting this equal to the torque from the angular acceleration, we get:

0.0975 a = 58.2587

Solving for a, we find a = 596.9745 m/s^2.

Now, let's use the kinematic equation s = ut + (1/2)at^2 to find the time t it takes for the basketball to roll 2.8 m down the incline. Since the basketball starts from rest, the initial velocity u is 0. Plugging in the values, we get:

2.8 m = (1/2) * 596.9745 m/s^2 * t^2

Simplifying, we find:

t^2 = (2 * 2.8 m) / 596.9745 m/s^2 = 0.0093462 s^2

Taking the square root of both sides, we get:

t = 0.0966546 s

Therefore, it will take approximately 0.097 s for the basketball to roll without slipping 2.8 m down the incline.

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