HW10.sol - homework 10 RAHMAN, TARIQUE Due: Feb 29 2008,...

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homework 10 – RAHMAN, TARIQUE – Due: Feb 29 2008, 3:00 am 1 Question 1, chap 7, sect 3. part 1 of 2 10 points If a golf ball and a ping-pong ball both move with the same kinetic energy, which has the greater speed? 1. Cannot be determined 2. the golf ball 3. the ping-pong ball correct 4. The two balls have the same speed. Explanation: Kinetic Energy is 1 2 mv 2 . According to the assumption 1 2 m golf v 2 golf = 1 2 m p p v 2 p p . Since m golf > m p p , it follows that v golf < v p p . Question 2, chap 7, sect 3. part 2 of 2 10 points In a gaseous mixture of massive molecules and light molecules with the same average KE, which have the greater speed? 1. the light molecules correct 2. Cannot be determined 3. They have the same speed. 4. the massive molecules Explanation: Since m massive > m light ,v massive < v light . Question 3, chap 7, sect 3. part 1 of 1 10 points A piece of paper of mass m is dropped from a height H , to the ±oor (height = 0). The force of air friction has magnitude f . The net work W net done on the paper is 1. W net = mg H . 2. W net = - f H . 3. W net = - mg H . 4. W net = f H . 5. W net = ( mg - f ) H . correct 6. W net = ( f - mg ) H . Explanation: Net work is the work done by net force, so W net = V F net · V D = ( mg - f ) H . Question 4, chap 7, sect 1. part 1 of 1 10 points A catcher “gives” with a baseball when catching it. If the baseball exerts a force of 473 N on the glove such that the glove is displaced 5.25 cm, how much work is done by the ball? Correct answer: 24 . 8325 J (tolerance ± 1 %). Explanation: Basic Concept: W net = F net d cos θ = F net d since θ = 0 cos θ = 1. Given: F net = 473 N d = 5 . 25 cm Solution: W net = F net d = (473 N)(0 . 0525 m) = 24 . 8325 J Question 5, chap 7, sect 3. part 1 of 3 10 points A 0 . 419 kg particle has a speed of 8 . 6 m / s at point A and kinetic energy of 9 . 8 J at point B . What is its kinetic energy at A ?
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homework 10 – RAHMAN, TARIQUE – Due: Feb 29 2008, 3:00 am 2 Correct answer: 15 . 4946 J (tolerance ± 1 %). Explanation: Given : m = 0 . 419 kg and v A = 8 . 6 m / s .
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HW10.sol - homework 10 RAHMAN, TARIQUE Due: Feb 29 2008,...

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