An object is at rest at (3 ,7 ,2 )(3,7,2) and constantly accelerates at a rate of 7/5 m/s^275ms2 as it moves to point B. If point B is at (5 ,0 ,9 )(5,0,9), how long will it take for the object to reach point B? Assume that all coordinates are in meters.

1 Answer
Jan 4, 2018

The time is =3.8s=3.8s

Explanation:

The distance ABAB is

AB=sqrt((5-3)^2+(0-7)^2+(9-2)^2)=sqrt(4+49+49)=(sqrt102)mAB=(53)2+(07)2+(92)2=4+49+49=(102)m

Apply the equation of motion

s=ut+1/2at^2s=ut+12at2

The initial velocity is u=0ms^-1u=0ms1

The acceleration is a=7/5ms^-2a=75ms2

Therefore,

sqrt(102)=0+1/2*7/5*t^2102=0+1275t2

t^2=10/7sqrt102t2=107102

t=sqrt(10/7sqrt102)=3.8st=107102=3.8s