A lump of lead with mass 0.5kg is dropped from height of 20m onto a hard surface it doesn't rebound but remains there at rest for a long period of time. A, find change in heat , change in work, change in internal energy for the lead during this process?
∆Q,∆W&∆U?
To find the change in heat, change in work, and change in internal energy for the lead during this process, we need to consider the concepts of potential energy, kinetic energy, work, heat, and internal energy.
1. Change in heat:
When an object collides with a surface and comes to a stop, some of its kinetic energy is converted into heat. In this case, the lead lump comes to rest on the hard surface, so all of its initial kinetic energy is converted into heat.
We can calculate the initial kinetic energy using the formula: Kinetic Energy = (1/2) * mass * velocity^2. Since the object is initially at rest, the initial velocity is zero. Therefore, the initial kinetic energy is zero.
Hence, the change in heat during this process is zero.
2. Change in work:
When the lead lump falls and strikes the hard surface, work is done by the gravitational force acting on the object. Work is calculated using the formula: Work = force * distance. In this case, the force is the gravitational force acting on the object, and the distance is the height from which the object is dropped.
The gravitational force is given by the equation: Force = mass * gravitational acceleration, where the gravitational acceleration on Earth is approximately 9.8 m/s^2.
Therefore, the work done is: Work = 0.5 kg * 9.8 m/s^2 * 20 m = 98 Joules.
Hence, the change in work during this process is 98 Joules.
3. Change in internal energy:
The change in internal energy refers to the change in the energy stored within the object itself. In this case, as the lead lump comes to rest and remains there, there is no change in its internal energy.
Therefore, the change in internal energy during this process is zero.
In summary:
- Change in heat: 0 Joules
- Change in work: 98 Joules
- Change in internal energy: 0 Joules.
gpe converted into heat: mass*g*height
all that energy changes to heat (internal energy). It came from the work gravity did.