# Repost physics

Suppose the position of an object is given by ->r(vector) = (3.0t^2*ihat - 6.0t^3*jhat)m. Where t in seconds.

Determine its velocity ->v as a function of time t.

Determine its acceleration ->a as a function of time t.

Determine ->r at time t = 2.5 s.

Determine ->v at time t = 2.5s.

I don't really understand the vector units and the answers require the i^ and j^ vector units. Please explain the significance, my prof didn't do justice in class.

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1. R = 3 t^2 i -6 t^3 j

V = dR/dt = 6 t i - 18 t^2 j

A = d^2R/dt^2 = dV/dt = 6 i - 36 t j

use 2.5 for t to get numbers

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posted by Damon
2. pweasey-weasy?

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posted by Han
3. thank you damon

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posted by Han

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