# Impact of running leached dog?

1. Nov 21, 2005

### Lorens

My problem is as follow!

A 45kg dog that is leached, starts to run and the line is all out when he have reach the speed of 20 m/s. The owner will experience a tweak. How do you approximate, this tweak?

My thinking is that it depend on how fast the deceleration are, according to this formula f=ma. But don’t know how to do that approximation I mean does it take 1 sec or two sec; am I missing something?

Then you can think in forum of energy (m*v^2)/2, but I don’t know were to go from there.

I am grateful for any tips!

Kindly Paul-Martin

2. Nov 21, 2005

### Chi Meson

Do we assume that the dog is brought to a stop? This is what I assume since no other "final speed" for the dog is given.

By "tweak" you must mean force? If so, you can't find this force unless you know one of the following: how much time does the "tweak" take, or how much distance does the dog/master move during the tweak.

You can make an approximation of the distance: let's say the tweak pulls the owners arm out to full length. How far will that be?

From this point consult the work-energy theorem which states that the net work done on an object equals its change in kinetic energy.

3. Nov 21, 2005

### Lorens

You ask some good questions, i don’t know, can’t test this, I just have to guess. It is a worst case scenario. So I am asking you guys to help me with the guessing.

Worst case scenario 1 guessing

1. A kid is holding the leach, with the weight of 40kg
2. How long does he move during impact, Unknown
3. What is the force which affect him f=-20*40/(t) t=time for deceleration to zero. set t=0.1...

I would be happy if anyone was better then me with the guessing!

4. Nov 21, 2005

### Lorens

You can make an approximation of the distance: let's say the tweak pulls the owners arm out to full length. How far will that be?

It wouldn’t be the full length, your hand would already be stretched as you are holding the leach, you would probably move in an angel instead. Also the power wouldn’t be evenly distributed, moving the hand would probably consume like 0.5% of the energy, after that we are in the same spot as before.