An object is at rest at #(7 ,8 ,4 )# and constantly accelerates at a rate of #5/4 m/s^2# as it moves to point B. If point B is at #(9 ,5 ,3 )#, how long will it take for the object to reach point B? Assume that all coordinates are in meters.

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Answer 1 · 2017-01-03T06:51:19

The answer is #=2.45s#

The distance betwwen A and B is

#=sqrt((9-7)^2+(5-8)^2+(3-4)^2)#

#=sqrt(4+9+1)#

#=sqrt14m#

We use the equation

#s=ut+1/2at^2#

#u=0#

So,

#sqrt14=1/2*5/4*t^2#

#t^2=8/5sqrt14=5.99s^2#

#t=2.45s#