CHAPTER 5: WORK, ENERGY, AND POWER A. Work 1. How much work is done in pushing a desk with a force of 280 N at a distance of 5 m? 2. A luggage is tilted at 30 to and pushed with a force of 21 N for 18 m toward the check in counter. How much work is done? B. Power 1. A box is being pulled with a force of 90 N at a rate of 8 m/s. How much power is produced? 2. Rose has a mass of 45 kg and ran up a stairs with 7.5 height in just 50s. How much power did she produce? C. Kinetic Energy 1. Find the KE of a 5,745g object that has a velocity of 17m/s.2. Who has the greatest KE among the 3 animals? Their average velocities are as follows: a lion that travels 22.35m/s, a tiger with 17.88m/s and a human with 13.21m/s. Their average mass is 190kg. 170kg, and 62kg respectively. E. Gravitational Potential Energy 1. Find the gravitational potential energy of the 15kg sack elevated at 15m. 2. A 60kg box is transported to a truck using a 15m inclined wood with an angle of 35 from the pavement. F. Elastic Potential Energy 1. A spring for the catapult was compressed by a 83 N force to 0.99m. a) Find the force constant of the spring. B) How much force is needed to compress the spring by 2.21m? c) What is the elastic potential energy if it is compressed by 0.2.5m? G. Work - Energy Theorem 1. The Flash is seen running after a train with a mass of 450,000kg moving at 62m/$2. A) Find how much force is acted on the train. B) Calculate the amount of work he needs to put up with to catch up. H. Center of Mass 1. A four-point particle is seen plotted in an x-y coordinate. The points have the following coordinates: (0m,0m); (0m,3m):(5m,0m); and (5m,3m) respectively with a mass of 1kg, 2kg, 3kg, and 4kg. Draw the four point particle and find the center of mass of this system then plot it. 1. Impulse-Momentum Theorem An armored service van with a mass of 3,500kg moving at a speed of 10.3m/s. a) What is the momentum of the van if there are 4 passengers with an average mass of 125kg and 5 sacks with an average mass of 15kg? b) What is its momentum if the 5 sacks are dropped along with 1 passenger but continues to move with the same speed and direction? J. Law of Conservation of Momentum An explosion occurred breaking an object into three parts. The mass of the object is 1kg. the first piece with a mass of 0.36kg traveled to the -y-direction at a speed of 2.5m/s while the second piece moved at a speed of 4m/s with a mass of 0.5kg to the + x-direction. Find a) the mass of the third piece and b) the horizontal and vertical component of its velocity. K. Collision 1. Two objects A with a mass of 4.7kg and B with a mass of 3.8g are approaching each other with velocities 5.5m/s and 9.8m/s respectively. Find the a) velocity after the impact assuming that this is a perfectly inelastic collision and b) the KE lost during the collision. 2. Problem above is changed into an elastic collision. A) How much kinetic energy is lost? B) How fast each mass is moving after colliding