JEE Main 20199 AprilEvening Shift
- Exam
- JEE Main
- Year
- 2019
- Date
- 9 April
- Shift
- Evening Shift
- Subject
- Physics
- Chapter
- Motion in One Dimension
JEE Main 2019 · 9 April · Evening Shift · Physics · Motion in One Dimension
The position vector of a particle changes with time according to...
The position vector of a particle changes with time according to the relation \overset{\to}{r}\left(t\right) = 15{t}^{2}\overset{^}{i} + \left(4 - 20{t}^{2}\right)\overset{^}{j} . What is the magnitude of the acceleration at
Options
- A
- B
- C
- D
Correct answer
D.
Step-by-step solution
\overset{\to}{r} = 15{t}^{2}\overset{^}{i} + \left(4 - 20{t}^{2}\right)\overset{^}{j}
\overset{\to}{v} = 30t\overset{^}{i} - 40t\overset{^}{j}
\overset{\to}{a} = 30\overset{^}{i} - 40\overset{^}{j}
At ,
\overset{\to}{a} = 30\overset{^}{i} - 40\overset{^}{j}
\left|\overset{\to}{a}\right| = 50