# Center of mass motion

## Homework Statement

The vector position of a 4.00 g particle moving in the xy plane varies in time according to
1 = (3i+3j)t +2jt^2
where t is in seconds and
is in centimeters. At the same time, the vector position of a 5.95 g particle varies as
2 = 3î − 2ît^2 − 6ĵt.
Determine the acceleration of the center of mass at t = 2.40.

## The Attempt at a Solution

A=-4i+4j
i took the second derivative of position to give me acceleration. This resulted in -4i+4j which is wrong[/B]

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Last edited:

gneill
Mentor
Can you show the details of how you arrived at your solution? Helpers won't simply confirm or deny a solution without work shown.

ehild
Homework Helper

## Homework Statement

The vector position of a 4.00 g particle moving in the xy plane varies in time according to
View attachment 2326741 = (3i+3j)t +2jt^2
where t is in seconds and View attachment 232675 is in centimeters. At the same time, the vector position of a 5.95 g particle varies as
View attachment 2326762 = 3î − 2ît^2 − 6ĵt.
Determine the acceleration of the center of mass at t = 2.40.

## The Attempt at a Solution

A=-4i+4j
i took the second derivative of position to give me acceleration. This resulted in -4i+4j which is wrong[/B]
You ignored the masses. How is the position of the center of mass defined?