Question

A particle starts with initial velocity is $(2\hat{i}+\hat{j})$m/s. Uniform acceleration $(-\hat{i}+3\hat{j})m/s^2$. What i y component of velocity at the instant when x component of velcoity becomes zero?

• A. 5 m/s
• B. 7 m/s
• C. 6 m/s
• D. 10 m/s

Answer 1

The correct option is B 7 m/s

Given :

Initial Velocity $U=(2i+j)m/s$

Uniform acceleration $a=(-i+3j)m/s^2$

Solution :

we have formula for velocity as V= U + at where V= final velocity

Case 1 (x component)

$V_x=U_x+a_{x}t$

$V_x=2-t$

We have to make $V_x=0$

so $2-t$ = 0 , t= 2sec

Case 2 (y component)

$V_y=U_y+a_{y}t$

$V_y=1+3\times 2$ = 7m/s

The Correct Opt = B