Mass, velocity, and time

[riseNshine]

Hi guys,

In projectile motion, regardless of mass, objects that start at the same height and velocity will reach the ground at the same time correct?

I've run into some problems where the answers state that the greater the mass of an object, the more quickly an object falls and the greater its terminal velocity...Do we only consider mass of the object in cases where we also account for terminal velocity? thanks.

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[molarseeker]

If you ignore wind resistance then they hit at the same time

 

[medicalman83]

Hi guys,

In projectile motion, regardless of mass, objects that start at the same height and velocity will reach the ground at the same time correct?

I've run into some problems where the answers state that the greater the mass of an object, the more quickly an object falls and the greater its terminal velocity...Do we only consider mass of the object in cases where we also account for terminal velocity? thanks.

You only consider mass when non-conservative forces are involved i.e. air resistance, friction. When air resistance is a factor....mass and surface area affect flight time.

 

[wjs010]

like others said, basically in perfect conditions ( like a vacuum I think) yes, they would hit at the same time.

 

[molarseeker]

Which pretty much means that the physics we learn is useless in real life.

 

[riseNshine]

Thanks for the clarification everyone