Home > Physics > Conservation of Momentum

A ball with a mass of #6 kg# moving at #16 m/s# hits a still ball with a mass of #10 kg#. If the first ball stops moving, how fast is the second ball moving? How much kinetic energy was lost as heat in the collision?

Answer 1

Elena Albarran

#9.6ms^(-1)#

KE loss#=307.2#

let us lay out what we know

Object 1

mass#=6kg#

initial velocity#" "u_1=16ms^(-1)#

Final velocity#" "v_1=0ms^(-1)#

Object 2

mass#=10kg#

initial velocity#" "u_2=0ms^(-1)#

final velocity#=v_2ms^(-1)" "#to find

we shall use the conservation of linear momentum

we have

#6xx16+10xx0=6xx0+10v_2#

#96=10v_2#

#=>v_2=9.6ms^(-1)#

KE loss

KE initial( before collision)#=1/2xx6xx16^2+0=768J#

KEfinal(after collision)#=0+1/2xx10xx9.6^2=460.8J#

#:." KE loss"=768-460.8=307.2J#

note that this is the total loss of KE. It doesn't all go into heat, some will go into other forms of energy for example sound.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Julia Aguilar

The second ball will move at a speed of 9.6 m/s. The amount of kinetic energy lost as heat in the collision is 460.8 joules.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.