# Newton's Cradle: Fascinating Momentum & Kinetic Energy

• John_RB
In summary, the Newton's Cradle is a fascinating object that demonstrates the conservation of momentum and kinetic energy in a simple way. For the balls to move away from the collision as they do, they must be identical and certain conditions must be met. If the balls are not of equal mass, there is a formula that can be used to calculate their collision behavior based on conservation of linear momentum and Newton's law of restitution. However, the behavior may not be as nice if the conditions are not met.
John_RB
I have always found the Newton's Cradle that my daughter bought for me fascinating. With the steel balls as identical as possible then the analysis of the process is simple. Both the momentum and kinetic energy are conserved (assuming negligible losses) on collision. The only way(?) this can occur is for the the same number of balls to move away from the collision as cause the collision; what is fascinating to me is how the balls which are hit move away as though glued together. Certain conditions must be met to get this nice simple behaviour. Both the receiving balls and the striking (raised) balls must be stationary and touching. If you do that then you can get several repeated collisions before the behaviour becomes "not so nice".
Is there an easy solution if the balls are not of equal mass and is the resulting collision always "not nice"?

you can use the direct formula which is based on conservation of linear momentum and Newton law of restitution (e) its a propert of colliding materials

#### Attachments

• 20150622_115806.jpg
38.1 KB · Views: 390
• 20150622_115926.jpg
43.5 KB · Views: 387

## Related to Newton's Cradle: Fascinating Momentum & Kinetic Energy

Newton's Cradle is a device that demonstrates the principles of conservation of momentum and kinetic energy. It consists of a series of metal balls suspended from a frame, with each ball connected to the next by a string. When one ball is lifted and released, it collides with the stationary balls, causing the last ball to swing out. This movement continues as the energy is transferred from one ball to the next, creating a mesmerizing back-and-forth motion.

Newton's Cradle was not actually invented by Sir Isaac Newton, despite its name. It was first demonstrated by Simon Prebble in 1967 and later popularized by actor Simon Prebble in 1971. However, the concept of conservation of momentum and kinetic energy was first described by Newton in his laws of motion.

## What principles does Newton's Cradle demonstrate?

Newton's Cradle demonstrates the principles of conservation of momentum and kinetic energy. This means that in a closed system, the total amount of momentum and kinetic energy remains constant, even when objects collide. In the case of the cradle, the moving ball transfers its momentum and kinetic energy to the stationary balls, causing them to move without any external forces.

## What is the significance of Newton's Cradle?

Newton's Cradle has become a popular educational tool and a symbol for the laws of motion. It is often used in classrooms to demonstrate the principles of physics and has also been featured in movies and TV shows. It also has practical applications, such as in impact testing for cars and other structures.

## Can Newton's Cradle be used to generate perpetual motion?

No, Newton's Cradle cannot be used to generate perpetual motion. While the balls appear to continue swinging forever, they eventually come to a stop due to the effects of friction and air resistance. Perpetual motion is impossible according to the laws of thermodynamics, which state that energy cannot be created or destroyed, only transferred or converted.

• Mechanics
Replies
53
Views
3K
• Mechanics
Replies
2
Views
253
• Mechanics
Replies
30
Views
2K
• Mechanics
Replies
3
Views
1K
• Mechanics
Replies
5
Views
1K
• Mechanics
Replies
2
Views
977
• Mechanics
Replies
4
Views
2K
• Mechanics
Replies
22
Views
3K
• Mechanics
Replies
34
Views
2K
• Mechanics
Replies
2
Views
2K