An object is at rest at (2 ,9 ,5 )(2,9,5) and constantly accelerates at a rate of 1/5 m/s15ms as it moves to point B. If point B is at (6 ,2 ,7 )(6,2,7), how long will it take for the object to reach point B? Assume that all coordinates are in meters.

1 Answer
Jul 29, 2017

t = 9.11t=9.11 "s"s

Explanation:

NOTE: I'll assume the given acceleration is 1/515 "m/s"^2m/s2, not 1/515 "m/s"m/s.

We're asked to find the time tt it takes an object to travel a certain distance with a given constant acceleration.

To do this, we can use the equation

Deltax = v_(0x)t + 1/2a_xt^2

where

  • Deltax is the distance it travels, which can be found using the distance formula:

Deltax = sqrt((6-2)^2 + (2-9)^2 + (7-5)^2) = 8.31 "m"

  • v_(0x) is the initial velocity, which is 0 since it started from rest

  • t is the time (we're trying to find this)

  • a_x is the constant acceleration (given as 1/5 "m/s"^2)

Plugging in known values, we have

8.31 "m" =0t + 1/2(1/5color(white)(l)"m/s"^2)t^2

t = sqrt((8.31color(white)(l)"m")/(1/10color(white)(l)"m/s"^2)) = color(red)(ul(9.11color(white)(l)"s"