Major Issues in Physics - Essay Example

The balloon would initially be at rest with zero momentum. On release, the gases initially inflated move in one direction and the balloon would move in the opposite direction to acquire equal momentum quantities such that the sum of the vector momenta become zero in line with Newton’s third law of motion that the forces are opposite and equal.

Had the rich man been not so miserly, he would have thrown the bag of gold coins so that while the bag glides in one direction, he would be propelled in the opposite direction in line with Newton’s third principle of motion which suggests that he would be propelled at an equal but opposite force to the one used to throw the bag. The ice being frictionless would cause the man not to stop until he reaches the shore.

In space, it would be expected that a rocket would have zero momentum as there is no force. To propel and change direction, the rocket thrusters push the fuel in one direction and fuel pushes back in the opposite direction in line with Newton’s third principle of motion. The rocket throws millions of particles from its tail causing it to move in the opposite direction referred to as spacecraft propulsion.

When the jar with orange juice is shaken vigorously, the work done would heat the juice thus increasing the molecules’ kinetic energy. This results in the juice components, which are pulp and liquid to mix and the froth to dissolve.

No. Temperature would not be exchanged between the two objects but the energy would. This proceeds until a thermal equilibrium is reached where both objects would have the same temperature. Their temperature change will however not essentially be the same.

a) No. For liquids and solids, the internal energies are complex and would involve potential energies affected by the bonds existing between molecules and atoms. Hence, objects could have the same temperature but different internal energies. Similarly, internal energy varies with object mass. When two objects of different temperatures are in contact with each other, there would be a transfer of net energy to the colder object from the hotter one no matter their internal energies.

b) Yes. For there to be energy transfer, there has to be a difference in temperature between two objects, which need not essentially be related to internal energies difference.

For a substance to change phase from solid to liquid to gas, energy should be supplied to break the intermolecular interactions. In water, these interactions make it as solid as ice. Ice would be hard because the interactions are strongest with the interaction weakening on transformation to steam or gas. When undergoing a phase change, energy would be consumed to break these interactions as opposed to causing an increase in temperature. As such, the temperature remains constant until that point where all the interactions would be broken. For example, when heat is applied to a block of ice, the temperature of the ice block would rise until it is 00C. The temperature remains constant as the block of ice melts to water as the absorbed heat would be used to break intermolecular bonds as opposed to increasing temperature. The temperature would then rise when all the ice melts to water.

No. The reverse is impossible. According to the second law of thermodynamics, no machine converts heat to mechanical energy hence no 100% efficient machines are referred to as heat engines (Serway, Faughn & Vuille, 2011). Some mechanical energy would be lost as heat. For example, a refrigerator is a reverse heat engine that takes the heat from inside and transfers it to the warmer outside. Heat pumps heat a building by cooling the air outside.

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