Helicopter Physics: Solving the Time of Release Problem

AI Thread Summary
To solve the problem of the time of release for an object dropped from a helicopter, it is essential to convert the speeds from mph to SI units. The equation of motion v = u + at is applicable, where v is the final speed (25 mph converted to m/s), u is the initial speed (2 mph converted to m/s), and a is the acceleration due to gravity. The correct signs must be used in calculations to ensure accuracy, as the initial speed will not be zero. By determining the time using these parameters, the passenger's wait time after lift-off can be calculated. This approach provides a clear method to solve the problem effectively.
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A helicopter's window is 5 ft above its skids. The helicopter starts on the ground and lifts straight into the air at a constant speed of 2 mph. A passenger in the helicopter drops an object from the window and the object hits the ground at 25 mph. How long did the passenger wait after lift off before releasing the object?

I am not sure what formulas to use for this problem and and do I want to figure out time final or time initial. Please help explain this to me.
 
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I'd look at this with an equation of motion:

Convert 2mph and 25mph to SI units.

Using v = u + at
where v = final speed, u = initial speed, a = acceleration due to gravity.

From there you can calculate t.

Note: Remember to get your signs right or your answer will be wrong, u will not be 0 to begin.
 

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