# Posts by Oisin

Total # Posts: 16

**Physics**

(b)A centrifuge has a maximum rotation rate of 10,000 rpm and can be stopped in 4 seconds. Assume the deceleration is uniform. The centrifuge radius is 8 cm. (i)What is the average angular acceleration of the centrifuge? (2%) (ii)What is the...

*August 12, 2010*

**Physics**

The flywheel is initially at rest. A force of 250 N is applied tangentially to the rim, causing it to rotate about its central axis. what is the energy acquired by it after 1 minute? can anyone help me with this?

*August 11, 2010*

**Physics**

(b)A centrifuge has a maximum rotation rate of 10,000 rpm and can be stopped in 4 seconds. Assume the deceleration is uniform. The centrifuge radius is 8 cm. What is the distance that a point on the rim travels during deceleration?

*August 9, 2010*

**Physics**

(ii) For the wheel of diameter 10 cm, find its final speed after traversing a distance of 10 m down an incline of 25º. Assume it starts from rest. I know i have to use the conversation of enrgy formula but how do i apply it to this instance?

*August 9, 2010*

**Physics**

Wow thanks very much I was usig the wrong formula for loss of PE that's where i went wrong its always helpful to have people to tell you where youve gone wrong

*August 5, 2010*

**Physics**

(i)For the wheel of diameter 10 cm, find its final speed after traversing a distance of 10 m down an incline of 25º. Assume it starts from rest. I know i have to use the conservation of energy but how? i don't understand where to start off

*August 5, 2010*

**Physics**

Show that the escape speed n for a body located on the surface of a planet of radius r and mass M is given by the expression v = sqrt( (2* G * M)/r) now im using (K+Ug)i = (K+Ug)k where Kf = 0 because final velocity is zero and Ugf = 0 because its final distance is infinity

*July 26, 2010*

**Phyics**

How is the change in entory calculated?

*July 21, 2010*

**Physics**

A car, of total mass 1200 kg, is travelling at 90 km/h and strikes a tree. The front end of the car compresses and the driver comes to rest after travelling 0.80 m. (i)What was the average acceleration of the driver during the collision? Express the answer in terms of “g...

*July 20, 2010*

**Physics**

A car, of total mass 1200 kg, is travelling at 90 km/h and strikes a tree. The front end of the car compresses and the driver comes to rest after travelling 0.80 m. (i)What was the average acceleration of the driver during the collision? Express the answer in terms of “g...

*July 20, 2010*

**Physics**

ii) Apply conservation of energy, making sure you count both translational and rotational KE now with this part Im not sure what you mean? i understand the conservation of energy but that wont give me the speed of the wheel

*July 20, 2010*

**Physics**

(b) Given that Icm = ½MR2 for a uniform solid wheel, (i) show that the rotational kinetic energy is half the translational kinetic energy for such a wheel. (ii) For the wheel of diameter 10 cm, find its final speed after traversing a distance of 10 m down an incline of...

*July 20, 2010*

**physics**

how did u find the angular velocity? im tryin to use v = wr but i don't know where to find the normal velocity of the rim

*July 20, 2010*

**physics**

no i mean to convert 45degrees into rads you multiply by 2pi thanks for your help

*July 20, 2010*

**physics**

so for the first part 20N * 0.2m * 2pi is that correct? also how did you get your torque? (iii) What is the angular momentum of the wheel after this time?

*July 20, 2010*

**physics**

A constant force of 20N is applied tangentially to a string wound on the rim of a 40 cm diameter wheel, initially at rest. (i) How much work does this force do as it turns the wheel through 45„a? (3 %) (ii) If the wheel has mass 8.0 kg and radius of gyration 15 cm, how ...

*July 20, 2010*

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