Question

While launching a satellite of mass $10^{4}kg$, a force of $5\times 10^{5}N$ is applied for $20s$. The velocity attained by the satellite at the end of $20s$, is

• A. $4km/s$
• B. $3km/s$
• C. $1km/s$
• D. $2km/s$

Answer 1

Answer: (C)

Given, mass of satellite, $m=10^{4}kg$
$F=5\times 10^{5}N,t=20s,u=0,v=?$
Impulse applied on the satellite is equal to the change in momentum.
i.e. $F\cdot t=m(v-u)$
$5\times 10^5\times 20=10^4(v-0)$
$\Rightarrow v=\frac{5\times 10^5\times 20}{10^4}$
$=1000m/s=1km/s$