Question

A particle moving along positive x-axis with a speed 5 ms^–1 suddenly changes its direction along the positive y-axis with the same speed. The change in velocity $\Delta\overset{\rightarrow}{v}$of the particle is -

• A. – 5($\widehat{i} + \widehat{j}$)ms^–1
• B. – 5($\widehat{i} - \widehat{j}$)ms^–1
• C. – 5(–$\widehat{i} + \widehat{j}$)ms^–1
• D. 5($\widehat{i} + \widehat{j}$)ms^–1

Answer 1

Answer: (B)

– 5($\widehat{i} - \widehat{j}$)ms^–1

Answer 2

${\overset{\rightarrow}{v}}_{1}$= 5$\widehat{i}$m/s${\overset{\rightarrow}{v}}_{2}$= 5$\widehat{j}$m/s

$\Delta\overset{\rightarrow}{v}$= ${\overset{\rightarrow}{v}}_{2}$–${\overset{\rightarrow}{v}}_{1}$= 5$\widehat{j}$ – 5$\widehat{i}$ = 5($\widehat{j}$–$\widehat{i}$) m/s