# Homework Help: Need help With This .

1. Mar 23, 2004

### hyen84

Need help With This.....

1.A force vector has a magnitude of 671 N and a direction of 65.8° north of east. Determine the magnitude of the components of the force that (a) point along the north-south line and (b) along the east-west line.

2.Airplane flight recorders must be able to survive catastrophic crashes. Therefore, they are typically encased in crash-resistant steel or titanium boxes that are subjected to rigorous testing. One of the tests is an impact shock test, in which the box must survive being thrown at high speeds against a barrier. A 45-kg box is thrown at a speed of 210 m/s and is brought to a halt in a collision that lasts for a time of 5.7 ms. What is the magnitude of the average net force that acts on the box during the collision?

2. Mar 23, 2004

### Chen

1. The force vector and its two axile components form a right triangle with an angle of 65.8°. Use the trigonometric functions sine and cosine to find the magnitudes of the axile components.

2. Using impluse and momentum:
$$\overline{F}\Delta t = m\Delta v$$
$$\overline{F} = m\frac{\Delta v}{\Delta t}$$
If you don't know about these, you can get to the same answer from Newton's law:
$$\overline{F} = ma = m\frac{\Delta v}{\Delta t}$$

Last edited: Mar 23, 2004
3. Mar 23, 2004

### hyen84

hey thanks for the help...i really appreciate it..but for some reason i used what you said and i got the answer wrong...i dunno where i did wrong..can someone double check for me..thanksssssssssssss

4. Mar 24, 2004

### Chen

Which question? And can you please show me what you did, so I can correct your methods if need be.