# Logs of Motion, how do i do this????

• Nov 20th 2008, 05:05 PM
freepancakes
Logs of Motion, how do i do this????
the question is....

position equation: x(t)= t ln t - 3t + c
Velocity equation: v(t)= ln t -2

a.) if particle is located at the orgin at t=1, find c and an equation for x(t)
b.) for what values of t is the particle moving to the left
• Nov 20th 2008, 05:23 PM
mr fantastic
Quote:

Originally Posted by freepancakes
the question is....

position equation: x(t)= t ln t - 3t + c
Velocity equation: v(t)= ln t -2

a.) if particle is located at the orgin at t=1, find c and an equation for x(t)
b.) for what values of t is the particle moving to the left

a.) Substitute x(1) = 0: 0 = 1 ln (1) - 3(1) + c => 0 = -3 + c => c = 3.
b.) v > 0 => moving to the right, v < 0 => moving to the left. Therefore. solve ln (t) - 2 < 0.
• Nov 20th 2008, 05:37 PM
freepancakes
what about the second part to letter a...and equation for x(t)

do i just plug what you found for C back into the original and thats my answer?
• Nov 20th 2008, 08:27 PM
mr fantastic
Quote:

Originally Posted by freepancakes
what about the second part to letter a...and equation for x(t)

do i just plug what you found for C back into the original and thats my answer?

Well, you're given x(t) aren't you .... except for the value of c, which has now been calculated .....