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A railway truck of mass 4 x 10exp4 Kg moves at 3ms-1 towards a stationary truck of mass 2 x 10exp4 Kg. the trucks collide and join calculate the total momentum of the two before the collision. What is the total momentum of the two trucks after the collision? Find the speed at which the joined trucks move off after their collision. Compare the kinetic energy after the collision with that before the collision.
Momentum= mass x velocity
4 x 10exp4 x 3ms-1 = 120000 Kg ms-1
2 x 10exp4 x 0ms-1 = 0 Kg ms-1 ( by stationary I take it, it means 0 ?)
Total momentum = 120000 + 0 = 120000
Total momentum after collision is equal to total momentum before collision if you exclude all other factors?
Speed ?
KE = ½mv2
If this is all wrong, which I am pretty sure it is, can you please show your full working.
Thanks.
Thats right. The suggestion you make is the method to use to solve the problem. So use it.
thats what I am having problems with, I rearranged it to give 'u' but it gave the wrong answer as the right answer is 9.5. but i dont know how to get this.
can someone show a worked example?
thanks
rocket powered sledge accelerates at 35ms-2 and takes 1.6s to pass through a 60m section of a test track. Find the speed at which it entered the section what was its speed when it left?
I think this is the equation to use x=ut + 1/2at2 and than use a=v-u/t to get v ?
a= 35m/s
t= 1.6s
u=?
v=?
x= 60m
please show your working
thanks
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