# Kinematics problem help

1. Sep 3, 2008

### Larrytsai

A fly falps its wings 1000 times per second. This means that the wing tip is accelerated from rest to a maximum velocity in 0.0025 seconds. If the wing tip travels 2mm in this time:

a) What is the average acceleration of the wing tip?
what i got is i converted 2mm to meters then multiplied that by 0.0025seconds
0.002 x 0.0025 = 8m/s
then i get lost from here i dont even think the first part was right.

b) What is the velocity at a maximum

2. Sep 3, 2008

### Banaticus

Re: Kinematics

The fly "flaps" its wings back and forth, right? It moves them up and down and up and down... So, it's accelerating and decelerating its wings all the time, changing the direction that they're moving. Average acceleration, the speeding up and the slowing down all averaged together, is zero.

Don't forget the common physics formulas:
$x(t)=x_0+v_0t+\frac{1}{2}at^2$
$v(t)=v_0+at$
$2a\Delta x=v^2-v_0\,^2$
$\Delta x=\frac{1}{2}(V+V_0)t$

The fourth problem seems like the formula that you want to use, but it's my understanding that this formula assumes constant acceleration and this isn't the case with your fly.

3. Sep 3, 2008

### Larrytsai

Re: Kinematics

Ohhhh that helps so much thanks alott, cant believe i missed that >.<