# Hi All. New To This

1. Feb 12, 2008

### phil555

Hi all, new to this. Studying my HNC in Mechanical Enginnering and was wondering if anyone can help with the below? I am struggling with the answers. Probs be quite easy to a few of you out there :rofl:.

2. (a) A flywheel has a mass of 100 kg and a radius of gyration of 150 mm.
It is accelerated from 100 rev min–1 to 250 rev min–1 at a constant
rate in 15 s. Calculate the power required to produce this
acceleration.

(b) A hammer of mass 80 kg falls 4 m onto a pile of mass 200 kg and
drives it 80 mm into the ground. If the energy loss is 2.24 kJ during
impact, calculate:

(i) the velocity of the hammer immediately before impact

(ii) the common velocity immediately after impact.

If the post is in the wrong place please relocate.

All help appreciated.

Kind regards,

Phil.

2. Feb 14, 2008

### phil555

anyone?????????

3. Feb 14, 2008

### mgb_phys

You have to at least make an attempt - there is no point us just telling you the answer!
Start with just the first part - list what you know and what equations you think you need.

4. Feb 14, 2008

### phil555

Will do. Still trying to work out which formula I need.

5. Feb 18, 2008

### phil555

Had a go. Is this correct?

6. Feb 18, 2008

### physixguru

EXCELLENT ...IS ALL WHAT I WOULD SAY..:P

But re look at your solution of part b. [3]

7. Feb 18, 2008

### phil555

Thanks. Which part in particular???? I come up with the same solution each time??????