Net force to a rocket

Classical Mechanics Level 1

A 500 -kg 500 \text{-kg} rocket is to be accelerated from rest to 1600 km/h 1600 \text{ km/h} at a constant rate in 1.8 1.8 seconds. What is the approximate magnitude of the required net force?

Assume the loss of fuel makes a negligible change to the mass of the rocket.

1.5 × 1 0 4 1.5 \times 10^4 N 1.2 × 1 0 5 1.2 \times 10^5 N 1.5 × 1 0 5 1.5 \times 10^5 N 1.2 × 1 0 6 1.2 \times 10^6 N

View wiki
Srinivasa Satti by Srinivasa Satti

This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try refreshing the page, (b) enabling javascript if it is disabled on your browser and, finally, (c) loading the non-javascript version of this page . We're sorry about the hassle.

6 solutions

mass = 5oo kg

final Velocity= 1600km/hr = 444.44m/s

Time = 1.8 s

v = u + at

444.44 = 0 + a*1.8

444.44/1.8 = a

246.91 = a

F = ma

F = 500*246.91

F = 1.2*10^5 N

28 Helpful 4 Interesting 7 Brilliant 2 Confused
Suchi Pattanayak
Jun 5, 2014

V = 1600 kmph = 444mps A = 444/1.8 mps2 F = MA = 1.2*10^5

6 Helpful 1 Interesting 1 Brilliant 0 Confused

can you please elaborate it?

Daniel Aberasturi - 6 years, 10 months ago

Log in to reply

Basically, drawing the free body diagram, you get the equation: F(net)=F(required)-mg, m=500kg, g≈10m/s², F(net)=ma=500kg×(444.44/1.8)m/s², you get a from the formula v=u+at. Thus you get F(req.)≈5000+123,456.79≈1.2×10^5 N

Aadi Naik - 6 years, 7 months ago
Kamaljeet Lakhina
Dec 17, 2014

3 Helpful 1 Interesting 3 Brilliant 1 Confused

gosh i forget to convert the velocity into m/s !!

Loexx Manncch - 6 years, 5 months ago
Pradeep Gb
Oct 9, 2014

f=m((v-u)/t) u=0,v=1600km/h=444m/s f=500(444/1.8)=1.2*10^5N

0 Helpful 0 Interesting 1 Brilliant 0 Confused
David Orrell
Dec 4, 2014

(1600km/h) / 3600 = (4/9)km/s ((4/9)km/s) * 1000 = 444.44m/s

a = Δv / t = (444.44 - 0) / 1.8s = 246.91358m/s/s

F = ma = 500kg * 246.91358m/s/s = 123456.79N ≈ (1.2 * 10^5)N

0 Helpful 0 Interesting 0 Brilliant 0 Confused
Vivek Singh
Nov 9, 2014

500* 1600 * 5 /1.8*18 =~1.2 *10 power5

0 Helpful 0 Interesting 0 Brilliant 0 Confused

0 pending reports

×

Problem Loading...

Note Loading...

Set Loading...