EX3.2-AirDrop - Copy

EX3.2-AirDrop - Copy - Does this equation help? Not too...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
A cargo crate is released from a plane traveling horizontally at 100 mph. The plane is 200 feet from the ground and is dropping the crate into a large lake. After the crate hits the water, assume that it travels in a straight line and has a deceleration (due to drag) of a= -1.2 v 2 ft/sec, where v is the magnitude of the crate’s velocity. How far along the straight line does the crate travel before it reaches a velocity of 2 ft/sec? 100 mph 200 ft s What type of problem? Curvilinear kinematics – doesn’t ask for forces. Calculate the velocity with which the box hits the water. The first part has constant acceleration, so can use those familiar physics equations.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Does this equation help? Not too much we dont really have time involved here. Probably better to use a different one. Which one? Now we know how fast it is going when it hits the water. Can I use: No!! a is not a function of ds. We have acceleration as a function of velocity, so I have to integrate with respect to velocity. That means I have to use one of these equations: dt dv a = vdv = ads Which one can I use? Set it up. Since it asks for a distance, we will want to use ads = vdv. What equation will I use now? Solve Given: Find: a(v), v f = 2 ft/s, v xi =100 mph, h= 200 ft s Sketch Solution:...
View Full Document

Ask a homework question - tutors are online