Ellowishous

Written Article Report

Brief Outline of Events in Article

A seven car commuter, carrying 580 passengers, derailed, crashing into an apartment complex killing 56 people and injuring 417 others. The crash happened in western Japan near Amagasaki, west of Tokyo.

Believed to be the worst train accident in four decades, two of the five derailed cars were flattened against the wall of the building. The train derailed at a curve after a straight in the tracks. The investigators struggled to find any real reasons for the crash, other than excessive speeds and failed braking procedures due to an inexperienced driver, and possible faulty breaking systems.

Events in Article Under Investigation

Quotes: "The crash happened on a curve after a straight requiring the driver to slow to 70 km/h" "Several passengers speculated the driver may have been speeding to make up for lost time"

"Train would of have had to be travelling at 133 km/h to jump the tracks purely because of excessive speed"

"The drivers inexperience may have been a factor"

From the information portrayed in the article the train derailed due to three main reasons:

#1. Excessive speeds

#2. Failed breaking systems/ procedures

#3. Straight > curve in tracks

Physics Laws and Principles involved in Article

-Newtons first law of motion

-Newtons second law of motion

- Momentum

-Circular Motion

Newtons First Law

"Any object will remain at rest or in a state of straight line motion unless an unbalanced force acts upon it."

If there is a net force acting on a body, then that force will affect that bodies motion. Basically, an unbalanced force acting on an object will change the shape or motion or will do both to the object. We often use these observations to find out if an unbalanced force is acting or not. If a net force does not act, the state of motion or rest of each object does not change, this property is inertia.

Force is not necessary to keep an object moving, the only reason objects slow down is due to friction. Friction is an unbalanced force which, when it is present acts in the direction opposite to motion of object.

Newtons Second Law

"The acceleration experienced by a body is directly proportional to the magnitude of the unbalanced force acting on it and is in the same direction as the force. It is inversely proportional to the mass of the object."

Newtons second law deals with changes in motion occurring, therefore when an unbalanced force acts on an object or body, there is a change in motion. Each time there is an unbalanced force applied, some form of acceleration occurs, thus a change in motion occurs. Acceleration and change in velocity are always in the same direction as an unbalanced force.

Formula: F=ma (F=force, m=mass, a=acceleration)

Written Article Report

Physics Laws and Principles involved in Article

Momentum

"The momentum of an object is the product of the mass and the velocity, and is a vector quantity having the same direction as the velocity"

"If no external force acts upon a system its total momentum is unchanged"

When ever an external force is applied to a body it's velocity will change and hence it's momentum will also change.(Related to Newtons second law of motion)

Formula: p=mv (p=momentum, m=mass, v=velocity)

Circular motion

Objects undergoing circular motion are accelerating towards the centre. Their speed is constant but their velocity is always changing. This acceleration towards the centre is called centripetal acceleration.

Formula: ac=v squared/ r (ac=centripetal acceleration, v=velocity, r= radius)

Since there is an acceleration, there must be a force. The force required to keep the mass moving in a circular path is called the centripetal force.

Formula: Fc=mv squared/r (Fc=centripetal force, m=mass, v=velocity, r=radius

In order for a mass to move in a circular path, a centripetal force is required. This force acts at right angles to the path of the body, without it the body would simply travel in a straight line( newtons first law) tangent to the circle. Centripetal force is actually the resultant of two unbalanced forces acting on the mass, the weight force down and the tension force.

Physics in Article Explaining Events

#1. The train approached the curve in the tracks with an extremely large velocity, and due to large mass, also with a very large momentum. As a result of inexperience or panic, the breaks were applied to quickly, resulting in a huge breaking attempt but small deceleration, in addition the braking system was faulty and unable to aid the driver in slowing the train.

#2. When the train reached the curve, it was not decelerated sufficiently and broke from the tracks carrying along the straight path of the previous tracks due to the large force behind the train.

According to Newtons first law of motion any object will remain at rest or in a state of straight line motion unless acted on by an external unbalanced force.

Given that an object is likely to keep doing what it's doing, in this case of the train, it was moving in a straight line with great velocity and force, therefore it was likely for it to keep moving straight and not take the curve as the external force( centripetal force) acting on it was insufficient and was overcome.

According to Newton second law of motion, the acceleration of a body is proportional to the force acting on it and inversely proportional to the to the mass of the object.

There fore as the train approached the curve, from the long straight stretch in the tracks, the attempted breaking, resulted in an insufficient deceleration, but due to Newtons second law of motion, still resulted in