Physics Essay Example | Topics and Well Written Essays - 750 words

Physics - Essay Example 3. 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. 4. 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. 5. 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 fuel in one direction and fuel pushes back in the opposite di rection 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. Phy 2-1 1. When the jar with orange juice is shaken vigorously, the work done would heat the juice thus increasing the molecules’ kinetic energy. ... 3. 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 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 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 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 solid as ice. Ice would be hard because the interactions are strongest with the interaction weakening on transformation to steam or gas. When undergoing phase change, energy w ould 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 on 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. Yes. It is possible to convert mechanical energy completely to heat or internal energy. No. The reverse is impossible. According to the second law of thermodynamics, there is no machine that converts heat to mechanical energy hence no 100%

How does fire frequency influence tree species diversity in the boreal Research Proposal

How does fire frequency influence tree species diversity in the boreal forest - Research Proposal Example Its unique characteristics are quickly changing as a result of human and natural pressure and this area is expected to be one of the most rapidly impacted regions of the world by the climate change that is ongoing which might lead to degradation of the Boreal eco systems in the end (Shvidenko & Apps, 2006). Canada is the largest producer and exporter of forest products with most of these products coming from the boreal forest that is there and therefore it may not come as a surprise that Canada has an advanced forest industry and also a forest management that is equally advanced. This has not stopped the forest in Canada from being significantly affected by changes that are occurring in the natural disturbances that include wild fire and insect outbreaks that have been taking place in the last few decades (Shvidenko & Apps, 2006). It is expected that the Boreal forest in particular will be vulnerable to disease, fire and competition from other tree species as the climate changes continue to be experienced and the weather gets warmer but the natural replacement in forest will take some time (Louiseize, 2005). Fire spread is not only a function of weather, but it also depends on topography, fuel load, types and spatial arrangement as well as active suppression and this therefore means that the fire spread simulations for everyday fire management require a large amount of information that is site specific (Pueyo, 2007). Being able to predict future fire activity that is related to climate change is a leap towards appreciating the future state of the Boreal ecosystem since the natural disturbances are usually controlled by the interplay between biotic and abiotic factors. Forest fire is the dominant natural disturbance that exists in Canada’s western Boreal forest where the fire regime of a particular area reflects the integration of