Question

A 500 kg rocket can be accelerated at a constant rate from rest to 1800 km/h in 2 sec. What is the magnitude of the required net force?

• A. 450,000 N
• B. 12,000 N
• C. 125,000 N
• D. 18,00,000 N

Answer 1

The correct option is C

125,000 N

As we know,

$F=\frac{\Delta p}{\Delta t}$

$\Delta P=m(v-u)=500v$

v = 1800 km/hr

= $\frac{1800\ast 1000}{3600}m/s$

= 500 m/s

$\therefore \Delta P=500(500-0)$

= 250,000 kg m/s

$F=\frac{250,000}{2}=125,000N$

$F_{net}=125,000N$