V1 = 90km/h = 90000m /3600s = 25 m/s.
V = 80km/h = 80000m/3600s = 22.2 m/s.
M1*V1 + M2*V2 = M1*V + M2*V.
M1*25+6000*0=M1*22.2 + 6000*22.2
25M1-22.2M1 = 6000*22.2.
2.78M1 = 133,200.
M1 = 47,952 kg. = 4.8*10^4 kg.
3. A train loaded with steel, moving at 90km/h, collides head on with a stationary train of mass 6000kg. if the trains couple after collision and move forward with a velocity of 80km/h, find the mass of the train loaded with steel.
My work so far:
PTO=PTF
mivi+m2v2=mvf
mi (25m/s)=(mi + 6000kg)(22.2m/s)
and then I get stuck here because I find it virtually impossible to solve for mi. I know the answer is suppose to be 4.8x10^4 kg though.
1 answer