A 4.0 kg circular disk slides in the x- direction on a frictionless horizontal surface with a speed of 5.0 m/s as shown in the adjacent Figure. It collides with an identical disk that is at rest before the collision. The collision is elastic. Disk 1 goes off at an 60 5.0 m/s angle of 60 with respect to the x-direction. Disk 2 g 30 goes off at an angle of 30 with respect to the x-direction. What best describes the speeds of the disks after the collision?

Solution :

Let kg

m/s

Let and are the speeds of the disk and  after the collision.

So applying conservation of momentum in the y-direction,

Therefore, the disk 2 have greater velocity and hence more kinetic energy after the collision.

Now applying conservation of momentum in the x-direction,

m/s

So,

          = 4.33 m/s

Therefore, speed of the disk 2 after collision is 4.33 m/s

f=ma a/f/m a= 480/60 a = 8m/s/s that is quick wow

show the wavelengths of a wave. show the crests of a wave.