Register to reply

Integrating to find distance and time - difficult!

by 1234john
Tags: difficult, distance, integrating, time
Share this thread:
1234john
#1
Apr23-10, 09:46 AM
P: 1
I have been looking for problems to work out for practice and came across one I have no idea how to even start about.

Say a box is dropped from a plane, with a parachute attached to it. If we are given two equations for velocity in terms of time, such as

Vx(t)=Vo cos(θ) e^(-pt) and Vy(t)=Vo sin(θ) - ge^(-z(t+6)) -16

If p is the drag coefficient in the x and z is the drag coefficient in the y.
θ would be the angle between the ground and the box.

Would θ not be a constant though since the angle will always be constant, even if the box follows a parabolic path?

And say the plane was flying level when the box was dropped... Wouldn't this mean that there is only an initial velocity in the x direction at whatever speed the plane was flying?

For practice, I made up p=0.061 and z=0.213

My whole dilemma is how I would find the time it takes for the box to hit the ground.

I'm fairly sure I'd have to take the integral which would give me distance. Plugging in zero for Vo in the y direction would cancel out the first part of the equation. θ would remain constant which would take out the sin and cos part of each equation and make it a constant.

I guess from there I am lost. My above assumptions could be wrong, however.

Please let me know! No rush on answering this as its just for my own personal practice and "fun".
Phys.Org News Partner Science news on Phys.org
Wildfires and other burns play bigger role in climate change, professor finds
SR Labs research to expose BadUSB next week in Vegas
New study advances 'DNA revolution,' tells butterflies' evolutionary history
reckon
#2
Apr23-10, 08:24 PM
P: 9
as Vo is y direction is zero
Vy(t)=-g exp(-z(t+6))-16

Vy=dy/dt, it makes
dy= (-g exp(-z(t+6))-16 )dt

and you get what you want


Register to reply

Related Discussions
How to find the acceleration given time and total distance Introductory Physics Homework 2
How to find the acceleration given time and total distance Introductory Physics Homework 1
Find time given velocity and distance Introductory Physics Homework 1
How do you find Acceleration when given Distance and Time? Introductory Physics Homework 3
Find time if boxes moved X distance Introductory Physics Homework 4