# How much thermal energy is produced in this collision?

• bosox3790
In summary, the first question involves using Hook's law to find the distance the spring will stretch when a mass of 2.7 kg is attached to it. The answer is 71.4 cm, with the spring starting at the 15 cm mark on the ruler. For the second question, the initial kinetic energy of the two railroad cars traveling at 100 km/h in opposite directions can be calculated. After the head-on collision, the cars come to rest and all of the kinetic energy is converted into thermal energy.
bosox3790
I cannot get these two questions at all. Can someone teach me how to do these?

A spring with k = 47 N/m hangs vertically next to a ruler. The end of the spring is next to the 15 cm mark on the ruler. If a 2.7 kg mass is now attached to the end of the spring, where will the end of the spring line up with the ruler marks?

Two railroad cars, each of mass 6500 kg and traveling 100 km/h in opposite directions, collide head-on and come to rest. How much thermal energy is produced in this collision?

first question:
Use Hook's law... F=kx
where F is the force that's pulling on the spring, which is the weight of the body that's hanging at the end. so...

(2.7)(9.81) = (47)(x)
x = 0.564m = 56.4cm
x is the distance the spring will stretch, so the end of the spring will end up at 15cm + 56.4cm = 71.4cm

bosox3790 said:
I cannot get these two questions at all. Can someone teach me how to do these?

A spring with k = 47 N/m hangs vertically next to a ruler. The end of the spring is next to the 15 cm mark on the ruler. If a 2.7 kg mass is now attached to the end of the spring, where will the end of the spring line up with the ruler marks?

Two railroad cars, each of mass 6500 kg and traveling 100 km/h in opposite directions, collide head-on and come to rest. How much thermal energy is produced in this collision?
Part deux: What is the initial kinetic energy of the cars combined? What is their final kinetic energy? Where did all that energy go??

## 1. What is thermal energy?

Thermal energy is a type of energy that is generated by the movement of particles in a substance. It is also known as heat energy and is a form of kinetic energy.

## 2. How is thermal energy produced in a collision?

In a collision, thermal energy is produced when the kinetic energy of the moving objects is converted into heat energy due to the friction between the colliding objects and the surrounding air or other objects.

## 3. How is the amount of thermal energy produced in a collision calculated?

The amount of thermal energy produced in a collision can be calculated using the formula Q = m x c x ΔT, where Q is the thermal energy, m is the mass of the objects, c is the specific heat capacity of the objects, and ΔT is the change in temperature.

## 4. What factors affect the amount of thermal energy produced in a collision?

The amount of thermal energy produced in a collision is affected by the mass and velocity of the colliding objects, the type of materials involved, and the surface area of contact between the objects.

## 5. How can the production of thermal energy in a collision be reduced?

The production of thermal energy in a collision can be reduced by using materials with lower specific heat capacity, reducing the speed of the colliding objects, and increasing the surface area of contact between the objects.

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