An object's two dimensional velocity is given by v(t)=(et2t2,tte2). What is the object's rate and direction of acceleration at t=1?

1 Answer
Jul 6, 2017

a=6.52 m/s2

ϕ=259o

Explanation:

We're asked to find the object's acceleration at time t=1 s from a given velocity equation.

To do this, we need to find the object's acceleration components as a function of t, via differentiation of the velocity equations:

Finding the derivative of velocity component equations, we have

vx=et2t2

vy=tte2

ax=ddt[et2t2]=et4t

ay=ddt[tte2]=1e2

At time t=1 s, the acceleration components are thus

ax=e(1)4(1)=1.28 m/s2

ay=1e2=6.39 m/s2

The magnitude (rate) of the acceleration is

a=(1.28lm/s2)2+(6.39lm/s2)2=6.52 m/s2

The direction of the acceleration is

ϕ=arctan(6.39lm/s21.28lm/s2)=78.7o +180o=259o

measured anticlockwise from the positive x-axis.

The 180o was added to fix the calculator angle error.