An object's velocity is given by v(t) = (t^2 +t +1 , t^3- 3t ). What is the object's rate and direction of acceleration at t=6 ?

2 Answers
Apr 23, 2016

vecv(t)=(t^2+t+1)hati+(t^3-3t)hatj
Differentiating w.r.t. twe have acceleration
veca(t)=d/(dt)(v(t))=(2t+1)hati+(3t^2-3)hatj
Acceleration at t=6 is
veca(6)=(2xx6+1)hati+(3xx6^2-3)hatj=13hati+105hatj
Magnitude of acceleration
|veca(6)|=sqrt(13^2+105^2)=105.8
Direction =tan^-1(105/13)~~83^o with the x-axis

Apr 23, 2016

a=105,80 " "(unit)/s^2

Explanation:

a(t)=d/(d t) v(t)" derivative of v(t) give us a(t)"

"derivative of v(t) for x direction:"
"..................................................."
a_x(t)=d/(d t)(t^2+t+1)

a_x(t)=2t+1

"fill in t=6"

a_x(6)=2*6+1=13

a_x(6)=13

"derivative of v(t) for y direction"
"..................................................."
a_y(t)=d/(d t)(t^3-3t)

a_y(t)=3t^2-3

"fill in t=6"

a_y(6)=3*6^2-3=3*36-3=108-3=105

"acceleration is a vector quantity so that we have to add " a_x and a_y " as vector"

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a=sqrt(13^2+105^2)

a=sqrt(169+11025)

a=sqrt(11194)

a=105,80 " "(unit)/s^2