P HY1ME1A Homework 5 Natividad Christian Russell PDF

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Assignment on Momentum and Collisions....

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NAME: CHRISTIAN RUSSELL A. NATIVIDAD SUBJECT/SECTION: PHYSICS FOR ENGINEERS / 1A DATE: MAY 2, 2021

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HOMEWORK 5

1. In splitting logs with a hammer and wedge, is a heavy hammer more effective than a lighter hammer? Why? • A heavy hammer would be more effective. The momentum of a heavy hammer is greater than that of a lighter hammer. As a result, a heavy hammer will apply more force to the logs than a lighter hammer, resulting in greater strength. 2. Suppose you catch a baseball and then someone invites you to catch a bowling ball with either the same momentum or the same kinetic energy as the baseball. Which would you choose? Explain. • Assume baseball has a density of m and a velocity of v. Let the bowling ball's letters be M and V. Same momentum: mv=MV=> the speed of a bowling ball is much slower than that of a baseball since it is much heavier. The KE of a bowling ball =0.5 MV2=0.5mvV is lower than the KE of a baseball (0.5 mv2). Same KE: 0.5 mv2=0.5 MV2=> much slower bowling ball speed than baseball speed. However, the momentum of a bowling ball =MV=((Mn)v) is even greater than that of a baseball mv. As a result, pick the same momentum since it has a lower KE.

3. When rain falls from the sky, what happens to its momentum as it hits the ground? Is your answer also valid for Newton’s famous apple? • Its momentum will be greater and greater as it gets closer to the ground because of the acceleration due to gravity. Yes, it is also valid for Newton’s apple. 4. A car has the same kinetic energy when it is traveling south at 30 m/s as when it is traveling northwest at 30 m/s. Is the momentum of the car the same in both cases? Explain • The vehicle in the first example was heading south at 30 m/s. In the second example, the same car travels northwest at the same 30 m/s level. Momentum is defined in Newtonian mechanics as mass multiplied by velocity. In both cases, the amount of momentum is the same if the mass travels in the same direction. 5. In a completely inelastic collision between two objects, where the objects stick together after the collision, is it possible for the final kinetic energy of the system to be zero? If so, give an example in which this would occur. If the final kinetic energy is zero, what must the initial momentum of the system be? Is the initial kinetic energy of the system zero? Explain. • Yes, it's quite likely. When a magnet and an iron are placed on a frictionless table, they can move towards each other and become attached, causing them to bind together and not move. In this case, the initial momentum should be zero, so momentum should be conserved. It is not necessary for the kinetic energy to be zero at the start. After a collision, however, energy may be transferred to other sources. Examples: fire, vibration.

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6. A machine gun is fired at a steel plate. Is the average force on the plate from the bullet impact greater if the bullets bounce off or if they are squashed and stick to the plate? Explain. • A value calculated in terms of a vector is referred to as "momentum." If the bullet follows the plate, the velocity difference is of magnitude p. Any of the bullet's final momentum will be antiparallel to its original momentum if it bounced. When this component is subtracted from a vector, the inverse is obtained, which increases the magnitude of the momentum transfer. 7. An egg is released from rest from the roof of a building and falls to the ground. As the egg falls, what happens to the momentum of the system of the egg plus earth? • Since the gravitational force acting on the egg and earth system comes solely from the egg and earth, there is no external force acting on them. As a result, the overall momentum of the system (egg + earth) remains unchanged.

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