# physics - drwls?

The flywheel of a steam engine runs with a constant angular speed of 250 rev/min. When steam is shut off, the friction of the bearings stops the wheel in 2.1 h.
At the instant the flywheel is turning at 75 rev/min, what is the tangential component of the linear acceleration of a flywheel particle that is 50 cm from the axis of rotation?

* physics - drwls, Monday, March 12, 2007 at 6:14am

The flywheel will decelerate at a uniform rate, since the frictional torque and moment of inertia can be sonsidered constant. That rate is
alpha = -(250 rev/min)*(2 pi rad/rev)*(60 min/sec)/[(2.1 hr)*(3600 sec/hr)]
Multiply that "alpha" by the radius to get the tangential component of acceleration for a point on the rim of the wheel. It will not matter what the rpm is at the time. RPM will affect the centripetal acceleration, however.

* physics - winterWX, Tuesday, March 13, 2007 at 12:43am

I tried that and got -6233 mm/s^2 or -6.23 m/s^2 but that is the wrong answer. What am I doing wrong? Thanks.

I don't see any error in the method I suggested. 50 cm x -12.5 rad/s^2 is not -6233 mm/s^2, so I don't know how you got that.

I did 500mm x -12.5 rad/s^2 and got -6250 mm/s^2 which are the units asked for but that is the wrong answer. Not sure what to do now.

Thanks for explaining what you did. It seems OK to me now. I'm sorry I cannot be of further assistance with this question.

In the conversion of min to seconds, how did you conclude that 60 min were in one second?

1. 👍
2. 👎
3. 👁

## Similar Questions

1. ### Physics

In a city with an air-pollution problem, a bus has no combustion engine. It runs on energy drawn from a large, rapidly rotating flywheel under the floor of the bus. The flywheel is spun up to its maximum rotation rate of 5150

2. ### Physics

Flywheels are large, massive wheels used to store energy. They can be spun up slowly, then the wheel's energy can be released quickly to accomplish a task that demands high power. An industrial flywheel has a 1.5 m diameter and a

3. ### Physics

Pilots can be tested for the stresses of flying high-speed jets in a whirling "human centrifuge," which takes 1.8 min to turn through 21 complete revolutions before reaching its final speed. 1. What is the angular

4. ### trigonometry

A Wheel of radius 14in. is rotating 0.5 rad/sec. What is the linear speed v, the angular speed in RPM ( rev per min), and the angular speed in deg/sec?

1. ### physics

A centrifuge in a medical laboratory rotates at an angular speed of 3,550 rev/min. When switched off, it rotates through 54.0 revolutions before coming to rest. Find the constant angular acceleration (in rad/s2) of the centrifuge.

2. ### physics

The flywheel of a steam engine begins to rotate from rest with a constant angular acceleration of 1.45 rad/s2. It accelerates for 29.5 s, then maintains a constant angular velocity. Calculate the total angle through which the

3. ### angular momentum

Just after a motorcycle rides off the end of a ramp and launches into the air, its engine is turning counterclockwise at 7530 rev/min. The motorcycle rider forgets to throttle back, so the engine's angular speed increases to 12600

4. ### Physics

A flywheel turning at 1200 rev/min (125.7 rad/s) constant angular velocity has a radius of 2.5 cm. As it turns, a string is to be wound onto its rim. How long is the string if it is wound up in 10 seconds? It says the answer is

1. ### candle

The flywheel of a prototype car engine is under test. The angular position θ of the flywheel is given by θ = (3.0rad/s3)t3 and the diameter of the flywheel is 36cm. (a)Find the distance that a particle on the rim moves during

2. ### physics

What is the angular speed in rev/min of the Earth as it orbits around the sun? I'm confused with this problem. I know we have to convert from rad/s to rev/rad to s/min in order to get the units as rev/min. But I don't know what to

3. ### physics

1. A centrifuge in a medical laboratory rotates at an angular speed of 3650 rev/min. When switched off, it rotates through 50.0 revolutions before coming to rest. Find the constant angular acceleration of the centrifuge. 2. A ball