Inertia - throwing a ball off of a moving train

[mak10]

The speed is the magnitude of the velocity. If the (instantaneous) velocity is zero, so is the speed.

 

ofcourse! i stand corrected! apologies for all the unwanted confusion!

 

-mak10

[TWJian]

Oops,sorry guys.I misunderstood the question.Severian,thanks for explaining things for me.

[IkeDillinger]

Speed is a scaler measurement, quantified by distance over time. Which gives you the rate/magnitude of speed an object travels over ground. Distance over time. Like fps/feet per second or mph/ miles per hour. 

Velocity is a vector measurement, it’s speed with a direction. 

A person holding a baseball in relation to the relative velocity of the train floor has a velocity of 0mph. Regardless of the trains speed. If you throw the ball in any DIRECTION inside the train it will move at 70mph.

If the ball is thrown straight out the back(opposite DIRECTION of travel) of a train at 70mph,  with the trains absolute velocity of  70mph relative to a fixed point on the ground the ball will travel through the train at a velocity of 70mph until the moment it leaves, then it’s velocity relative to the fixed point is 0mph.

Thrown at 70mph directly off the back of a train going 70mph from 10ft off ground level, an onlooker would see the ball drop straight down and hit the ground in 3/4 of a second. 

Edited March 18, 2020 by IkeDillinger

[michel123456]

Mythbusters, look at 1min if you are more impatient than the impatient.