Instructions: Work the following sample problems over basic circular motion equations. Write the complete equation
you used to solve the problem, show how you set up the numbers, solve for the unknown, and indicate your final answer
with units.
1) A festive Mardi Gras merry-go-round is spinning with an angular velocity of 25 rotations per minute. There is an angular acceleration due to frictional torque of 0.5 rad/s² opposed to
this motion. The merry-go-round has a 3 meter diameter. Let's do a "full solve" of this problem.
A) How many seconds does it take for the merry-go-round to stop?
B) How many rotations does the merry-go-round go through during this time?
C) What is the linear acceleration of a point on the edge of the merry-go-round?
D) What are the initial and final linear velocities of the merry-go-round's edge in this time interval?
E) What is the arc length (scalar distance) that a point on the edge of the merry-go-round moves?
2) A) An electric motor is spinning a metal 0.75 m radius silver platter with a King Cake on it, but it begins speeding
due to a malfunction. It is given an angular acceleration of 0.9 rad/s². If the platter rotates 5 complete times before its angular velocity doubles, then what was the initial and final
angular velocity?
B) If a slice of King Cake starts sliding off the platter if the linear velocity exceeds 4.5 m/s, then what is the maximum distance the center of mass of the food can sit from the middle of the platter and remain where
it is a both angular velocities?

Respuesta :

Answer:

I can help you solve the sample problems involving basic circular motion equations.

Explanation:

Let's address each part step by step:

1) A festive Mardi Gras merry-go-round:

A) To find the time it takes for the merry-go-round to stop:

Equation used: \[ \text{final angular velocity} = \text{initial angular velocity} + \text{angular acceleration} \times \text{time} \]

\[ 0 = 25 \text{ rotations/min} - 0.5 \text{ rad/s}^2 \times \text{time} \]

Solving for time gives: \[ \text{time} = \frac{25 \text{ rotations/min}}{0.5 \text{ rad/s}^2} \times \frac{2\pi \text{ rad}}{1 \text{ rotation}} \times \frac{1 \text{ min}}{60 \text{ s}} \]

B) To determine the number of rotations during this time:

\[ \text{rotations} = \text{initial angular velocity} \times \text{time} + 0.5 \times \text{angular acceleration} \times \text{time}^2 \]

C) To find the linear acceleration of a point on the edge:

\[ \text{linear acceleration} = \text{radius} \times \text{angular acceleration} \]

D) For initial and final linear velocities:

Initial linear velocity: \[ \text{initial linear velocity} = \text{initial angular velocity} \times \text{radius} \]

Final linear velocity: \[ \text{final linear velocity} = 0 \]

E) The arc length that a point on the edge moves:

\[ \text{arc length} = \text{radius} \times \text{angle in radians} \]

2) A) For the electric motor spinning the silver platter:

To find initial and final angular velocities:

\[ \text{final angular velocity} = \text{initial angular velocity} + \text{angular acceleration} \times \text{time} \]

B) Maximum distance the center of mass of the food can sit from the middle of the platter:

Use the relation between linear and angular velocity: \[ \text{linear velocity} = \text{radius} \times \text{angular velocity} \]

By following these steps and equations, you can solve the given sample problems on circular motion effectively.