A stationary particle explodes into 3: A (to the left), B and C (both to the right). B has mass m and speed 3v. C has mass 2m and speed v. A has speed 2v. What is the mass of A in terms of m?

The key to solving this is remembering that momentum is conserved. The large, initial particle has no speed so its momentum is zero. Therefore, if we add together the momenta of the final particles we also get zero. So we can write:

pA + p+ p= 0

And we can rearrange for pA, which is what we want to find:

pA = -pB - pC

We know that momentum is calculated p = mv and we are given the masses and velocities of B and C, and the velocity of A (we remember that A is travelling in the opposite direction so has a negative v):

M* (-2v) = -3mv - 2mv

We rearrange for the mass of A, MA, and find that:

MA = 2.5 m

SP
Answered by Seth P. Physics tutor

2091 Views

See similar Physics A Level tutors

Related Physics A Level answers

All answers ▸

Bernard says that a mass executing uniform circular motion is not accelerating as it's speed is not changing. Which parts of his statement are correct and which are false. For those which are false state why they are and give the correct version.


What is the Doppler Effect?


If a wire loop moves at constant speed into a region where there is a magnetic field, why is a current induced in the wire?


In the Photoelectric Effect, what is mean by 'threshold frequency' and how does the magnitude a photons frequency effect the electron it is absorbed by?


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2025 by IXL Learning