The radius of the Earth is 6,400km and has a mass of 6x10^24kg. Calculate the minimum velocity needed by a projectile, fired from the surface of the Earth in order to escape the Earths gravity.

First we write down the relevant information given in the question. Re = 6,400km = 6.4 x 106 m, Me = 6 x 1024 kg.For the projectile to escape the Earths gravity, the projectile must be launched with a kinetic energy which is greater than the amount of work needed to overcome Earths gravity, or Earth's gravitational potential. To find the minimum velocity required, we equate kinetic energy and gravitational potential on Earths surface and rearrange for velocity.
-GMm/R = 0.5mv2
Hence, v2 = -2GM/R, so vesc = sqrt(-2GM/R)Inputting the values gives an escape velocity of vesc = 11200 ms-1 to 3 s.f

Answered by Neil C. Physics tutor

5862 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

A conical pendulum is a mass suspended from a point that traces out a horizontal circle. By balancing the weight with the tension in the string, determine the speed of the bob.


Two railway trucks of masses m and 3m move towards each other in opposite directions with speeds 2v and v respectively. These trucks collide and stick together. What is the speed of the trucks after the collision?


Calculate the flight time of a ball moving in parabolic motion, with initial velocity 5.0m/s at angle 30 degrees from the horizontal travelling for 23 metres.


One of the decays of potassium (A=40, Z=19) results in an excited argon atom with excess energy of 1.50 Mev. In order to be stable, it emits a gamma photon. What frequency and wavelength has this gamma photon?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences