Question:

A particle has an initial velocity $3\hat{i}+4\hat{j}$ and an acceleration of $0.4\hat{i}+0.3\hat{j}$. Its speed after $10\, s$ is

Updated On: Jul 5, 2022
  • $10$ units
  • $7\sqrt{2}$ units
  • $7$ units
  • $8.5$ units
Hide Solution
collegedunia
Verified By Collegedunia

The Correct Option is B

Solution and Explanation

$\overrightarrow{u}=3\hat{i}+4\hat{j} ; \overrightarrow{a}=0.4\hat{i}+0.3\hat{j}$ $\overrightarrow{u}=\overrightarrow{u}+\overrightarrow{a}t$ $=3\hat{i}+4\hat{j}+\left(0.4\hat{i}+0.3\hat{j}\right)10=3\hat{i}+\hat{j}+4\hat{i}+3\hat{j}=7\hat{i}+7\hat{j}$ Speed is $\sqrt{7^{2}+7^{2}}=7\sqrt{2}$ units
Was this answer helpful?
0
0

Concepts Used:

Motion in a Plane

It is a vector quantity. A vector quantity is a quantity having both magnitude and direction. Speed is a scalar quantity and it is a quantity having a magnitude only. Motion in a plane is also known as motion in two dimensions. 

Equations of Plane Motion

The equations of motion in a straight line are:

v=u+at

s=ut+½ at2

v2-u2=2as

Where,

  • v = final velocity of the particle
  • u = initial velocity of the particle
  • s = displacement of the particle
  • a = acceleration of the particle
  • t = the time interval in which the particle is in consideration