A body of mass $5\, kg$ starts from the origin with an initial velocity $\overrightarrow {u\,} \, = \,30\hat i + 40\hat j\,m{s^{ - 1}}$. If a constant force $\overrightarrow {F\,} = - (\hat i + 5\hat j)N$ acts on the body, the time in which the y-component of the velocity becomes zero is ......... $\sec$
A body of mass $5\, kg$ starts from the origin with an initial velocity $\overrightarrow {u\,} \, = \,30\hat i + 40\hat j\,m{s^{ - 1}}$. If a constant force $\overrightarrow {F\,} = - (\hat i + 5\hat j)N$ acts on the body, the time in which the y-component of the velocity becomes zero is ......... $\sec$
$5$
$20$
$40$
$80$
A body of mass $5\, kg$ starts from the origin with an initial velocity $\overrightarrow {u\,} \, = \,30\hat i + 40\hat j\,m{s^{ - 1}}$. If a constant force $\overrightarrow {F\,} = - (\hat i + 5\hat j)N$ acts on the body, the time in which the y-component of the velocity becomes zero is ......... $\sec$
${u_y} = 40\,m/s$, ${F_y} = - 5N$, $m = 5\,kg$.
So ${a_y} = \frac{{{F_y}}}{m} = - 1\,m/{s^2}$ (As $v = u + at$)
${v_y} = 40 - 1 \times t = 0$ $⇒$ $t = 40\,\sec $.
Other Language