Question

Find the magnitude of the angular acceleration at the moment $t=10.0s$.

• A. $1.3rad/s$
• B. $3rad/s$
• C. $1rad/s$
• D. $0.3rad/s$

Answer 1

The correct option is A $1.3rad/s$

$\overrightarrow{\omega }=at\overrightarrow{i}+b{t}^2\overrightarrow{j}$
$\overrightarrow{\alpha }=\frac{d}{dt}(at\overrightarrow{i}+b{t}^2\overrightarrow{j})=a\sqrt{1+{\left(\frac{2bt}{a}\right)}^2}=0.5\times \sqrt{(1+5.96)}=0.5\times 2.64=1.32rad/s$