An object is at rest at (1,2,9) and constantly accelerates at a rate of 1ms2 as it moves to point B. If point B is at (3,1,4), how long will it take for the object to reach point B? Assume that all coordinates are in meters.

1 Answer
May 23, 2017

3.31s

Explanation:

We're dealing with one-dimensional motion with constant acceleration.

What we can do first is find the displacement s during the time interval from point A to point B by using the three-dimensional distance formula:

s=(3m1m)2+(1m2m)2+(4m9m)2=5.48m

Let's look at our known quantities:

Since the object is initially at rest, v0x=0

We'll make the initial position x0 be 0, and the position x at time t be 5.48m

The acceleration is constant at 1ms

To find the time duration t of the displacement s, we can use the equation

x=x0+v0xt+12axt2

And since the initial velocity and position are both 0, the equation becomes

x=12axt2

Here, the variable x is analogous to the displacement variable s, since they both represent the distance covered. Plugging in the known variables ax and x, the time t elapsed during the displacement is

5.48m=12(1ms2)t2

t= 2(5.48ms)1ms2=3.31s