physics
posted by kdhgwiu
need help on this three part one
its about inelastic collisions momentum and energy related with work
Find the speed at which Superman (mass=76.0 kg) must fly into a train (mass = 17620 kg) traveling at 60.0 km/hr to stop it.
Running into the train at that speed would severely damage both train and passengers. Calculate the minimum time Superman must take to stop the train, if the passengers experience an average horizontal force of 0.430 their own weight.
How far does the train then travel while being slowed to a stop?

bobpursley
first, use conservation of momentum to find superman must fly.
Second, use impulse=change of momentum
You are given the average force.
averageforce*time=weight/g *velocity
.43avgweight*tim=avgweigh/g *velocity
solve for time
Lastly, the average velocity stopping is 30km/hr, you know the time, so solve for distance. 
derek
first part:
Pi=Pf
Pf=0 (train is not moving)
0= m1v1 + m2v2
v2=m1v1/m2
Respond to this Question
Similar Questions

physics
Find the speed at which Superman (mass=89.0 kg) must fly into a train (mass = 19564 kg) traveling at 65.0 km/hr to stop it. The system (train + Superman) must end up with zero momentum. With no external forces, Superman's initial momentum … 
Physics
A bullet with a mass of 55 grams moving with a speed of 100 m/s slams into and wedges in a 1.9 kilogram block of wood supported by a string initially at rest. Which one, conservation of energy or conservation of momentum, can be applied … 
Physics
Find the speed at which Superman (mass=88.0 kg) must fly into a train (mass = 17998 kg) traveling at 60.0 km/hr to stop it. Running into the train at that speed would severely damage both train and passengers. Calculate the minimum … 
Physics
Find the speed at which Superman (mass=88.0 kg) must fly into a train (mass = 17998 kg) traveling at 60.0 km/hr to stop it. Running into the train at that speed would severely damage both train and passengers. Calculate the minimum … 
physic
Superman must stop a 120km/h train in 150m to keep it from hitting a stalled car on the tracks.If the train's mass is 3.6x10^5kg,how much force must he exert? 
physic
Superman must stop a 120km/h train in 150m to keep it from hitting a stalled car on the tracks.If the train's mass is 3.6x10^5kg,how much force must he exert? 
college physics
Superman must stop a 190km/h train in 180m to keep it from hitting a stalled car on the tracks. part a)If the train's mass is 3.8×10^5kg , how much force must he exert (find the magnitude)? 
@elena
thank you so much help with the problem. i have trouble solving part b of the problem you helped me with. it told me to give it as a percentage, I got 10% but it is wrong. can you please help me Superman must stop a 190km/h train … 
physicsmechanicscollisions,momentum, impulse
You are at the controls of a particle accelerator, sending a beam of 2.40×107 protons (mass ) at a gas target of an unknown element. Your detector tells you that some protons bounce straight back after a collision with one of the … 
AP Physics  collisions?
Two steel balls collide and bounce apart in an isolated system. If the final kinetic energy is less than the initial kinetic energy, what of the following is true?