How can I solve for the mass of the first car in an elastic collision problem?

Thread starter tony873004
Start date May 3, 2005
Tags

Algebra Collision Elastic Elastic collision

AI Thread Summary

To solve for the mass of the first car (m1) in an elastic collision problem, the relevant equations include the conservation of momentum and kinetic energy principles. The equation m1 = (-u2 * m2) / (u2 - 2v1) is derived from rearranging the momentum conservation equation. The discussion highlights the importance of correctly applying these principles to isolate m1. The solution provided by a user named whozum was confirmed to be effective. This approach clarifies how to manipulate the equations to find the desired mass in collision scenarios.

May 3, 2005

tony873004

Science Advisor

Gold Member

In an elastic collision problem, I'm supposed to solve for the mass of the 1st car (m1). I get stuck here. How do I re-write this to solve for m1?

u_2=\frac{2*m_1v_1}{m_1+m_2}

Physics news on Phys.org

May 3, 2005

whozum

Thats the equation for an inelastic collision, but

u_2m_1+u_2m_2-2m_1v_1 = 0

u_2m_1 - 2m_1v_1 = -u_2m_2

m_1(u_2 - 2v_1)= -u_2m_2

m_1 = \frac{-u_2m_2}{u_2-2v_1}

May 3, 2005

tony873004

Science Advisor

Gold Member

Thanks, whozum. That worked !

Thread 'I've come across another fluid pressure problem I don't understand'

Neglect gravity other than that of water; neglect friction. F1=ρgsh=1000*10*1*(1+4)=50000 N; F1=ρgsh=1000*10*0.1*4=4000 N; F3=50000-4000=46000 N?

View full post »

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...

View full post »

Thread 'Understanding Forces and their Vector Components'

I was told forces are vectors so they can be divided into x and y components, but what about the normal force or the force of static friction? do you divide those into x and y components if say you had a block that was lying on an angled surface?

View full post »