# Recent content by spaceshipone

1. ### Acceleration Deceleration Physics Problem

A car has a maximum constant acceleration of 10 ft/s^2 and a maximum constant deceleration of 15 ft/s^2. determine the minimum amount of time it would take to drive one mile assuming the car starts and ends at rest and never exceeds the speed limit 55 mi/hr. Why do you need to know the...
2. ### Free-fall formula, adding air resistance

That problem is close but different. It looks like that if for something being thrown up with air resistence and they are solving for max height it will reach. My problem is as follows: A sky diver with a mass of 75 kg jumps from an aircraft. The aerodynamic drag force acting on the sky...
3. ### Free-fall formula, adding air resistance

I think the solution if you want to find time it took to travel say 100 meters will involve the chain rule (dx/dt)(dt/dv) or something like that, but i'm not sure how to incorporate that.
4. ### Free-fall formula, adding air resistance

Everything you guys said makes sense, but what are the limits for the separable integrals? If you want to find the time if takes after 100 m of free fall, what do you for for the limits for the left side dv and right side dt?
5. ### Spring Problem, Work

I don't understand. The force for this problem isn't constant. It varies as the direction changes.
6. ### Spring Problem, Work

Hi, Thanks for all the replies. If I used the dot product here is what I've come up with W = F dot dr so W = fs dot <.4 , 0> W = <40(l - .2), angle 221.4 degrees> dot <0 ,0.4> So I'm not sure where to go from here. I know the distance part is straightforward. It's just straight up. The force...
7. ### Maximum Stress on a wheel in motion

I would think you'd need to at least know the modulus E of the material to find the max allowable stress?
8. ### Spring Problem, Work

I've been trying for a while to solve this problem http://www.flickr.com/photos/36633646@N03/3379407472/ Do I just find the total force the spring exerts from 400mm to 0 and multiply it by distance b?