Question

The position of a particle is given by $\overrightarrow{r} = 3t\widehat{i} + 2t\widehat{j} + 5\widehat{k}$, where t is in seconds and the coefficients have the proper units for $\overrightarrow{r}$to be in metres. The acceleration of the particle at t = 1 s is

• A. $2\widehat{j}ms^{- 2}$
• B. $- 2\widehat{j}ms^{- 2}$
• C. $4\widehat{j}ms^{- 2}$
• D. $- 4\widehat{j}ms^{- 2}$

Answer 1

Answer: (C)

$4\widehat{j}ms^{- 2}$

Answer 2

For the questions number 31

$\overset{\rightarrow}{v} = 3\widehat{i} + 4t\widehat{j}ms^{- 1}$

$\therefore$Accelerations , $\overrightarrow{a} = \frac{d\overset{\rightarrow}{v}}{dt} = 4\widehat{j}ms^{- 2}$

Accelerations of the particle remains constant at all times.