Practicing Success

Target Exam

CUET

Subject

Physics

Chapter

Laws of Motion

Question:

A particle of mass 2 kg moves with an initial velocity of \(\vec{v} = 4 \hat{i} + 4 \hat{j}\) m/s. A constant force of \(\vec{F} = - 20 \hat{j}\) N is applied on the particle. Initially, the particle was at (0, 0). the x-coordinate of the particle when its y-coordinate again becomes zero is given by :

Options:

1.2 m

4.8 m

3.2 m

6.0 m

Correct Answer:

3.2 m

Explanation:

\(\vec{a} = \frac{\vec{F}}{m} = - 10 \hat{j}\) (m/s)2

Displacement in y-direction : y = ut + \(\frac{1}{2}\) at2

\(\Rightarrow 0 = 4*t*\frac{-1}{2}*10*t^2\)

\(t = \frac{4}{5} \text{ s}\)

\(\Rightarrow x = 4 t\)

\(\Rightarrow x = 4*\frac{4}{5}\)

\(\Rightarrow x = 3.2 \text{ m}\)