The search for the correct answer in this moment is a breeze. clickanswer.us offers accurate questions and answers. we offer a concise answer key and complete with the discussion. We offer a variety of answer keys that span from elementary, junior high and higher level schools. We offer subjects like biology, math, physics as well as economics, history, and others. Below are the question and answer keys that we have compiled from various sources on the internet.

## Question:

A heavy flywheel is accelerated (rotationally) by a motor that provides constant torque and therefore a constant angular acceleration α. The flywheel is assumed to be at rest at time t=0 in Parts A and B of this problem.

Part A

Find the time t1 it takes to accelerate the flywheel to ω1 if the angular acceleration is α.

Express your answer in terms of ω1 and α.

Part B

Find the angle θ1 through which the flywheel will have turned during the time it takes for it to accelerate from rest up to angular velocity ω1.

Express your answer in terms of some or all of the following: ω1, α, and t1.

Part C

Assume that the motor has accelerated the wheel up to an angular velocity ω1 with angular acceleration α in time t1. At this point, the motor is turned off and a brake is applied that decelerates the wheel with a constant angular acceleration of −5α. Find t2, the time it will take the wheel to stop after the brake is applied (that is, the time for the wheel to reach zero angular velocity).

Express your answer in terms of some or all of the following: ω1, α, and t1.

## Answer:

**(A)** The** time** taken by the flywheel for the acceleration is, .

**(B) ** The** angle **turned by the flywheel is .

**(C)** The **time** taken by the flywheel to stop after the brake is applied is .

**Given data:**

The magnitude of** angular acceleration** is, .

Final **angular speed** is, .

Time taken is, .

(A)

Apply the **first rotational equation** of motion as,

Since, the flywheel was initially at rest. So, . Then,

Thus, the **time taken** for the** acceleration** is, .

(B)

Now apply the **second rotational equation** of motion to obtain the angle turned by the flywheel as,

Substituting the values as,

Thus, the **angle turned** by the flywheel is .

(C) During acceleration, the expression is given as,

Since, **brake is applied**. Which means the flywheel is **stopped finally**. So, applying the **third rotational equation of motion** as,

Here, is the **final speed** after brake is applied. And its value is .

Solving as,

Thus, the **time taken** by the flywheel to stop after the brake is applied is .

Learn more about the rotational kinematics here:

You can use the answer key above as a reference when studying at home or at school. Thank you for stopping by, hopefully it will be helpful to everyone.