What is the speed of an object that travels from #( 7 , -4, 3 ) # to #( -2 , 4, 9 ) # over #4 s#?

1 Answer
Apr 28, 2016

Answer:

#s=d/t=(13.45m)/(4s)=3.36# #ms^-1#

Explanation:

First find the distance between the points, assuming distances are in metres:

#r=sqrt((x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2)#
#=sqrt(((-2)-7)^2+(4-(-4))^2+(9-3)^2)#
#=sqrt(-9^2+8^2+6^2)=sqrt(81+64+36)=sqrt181~~13.45# #m#

Then speed is just distance divided by time:

#s=d/t=13.45/4=3.36# #ms^-1#