Practice Questions for Exam 1-solutions

Practice Questions for Exam 1-solutions - markowitz...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: markowitz (am45362) Practice Questions for Exam 1 distler (56295) 1 This print-out should have 11 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A freight train has a mass of 2 . 5 10 7 kg. If the locomotive can exert a constant pull of 5 . 4 10 5 N, how long would it take to increase the speed of the train from rest to 89 . 2 km / h? Disregard friction. Correct answer: 1147 . 12 s. Explanation: Let : m = 2 . 5 10 7 kg F net = 5 . 4 10 5 N v f = 89 . 2 km / h vector F net = summationdisplay vector F = mvectora a = F net m = 5 . 4 10 5 N 2 . 5 10 7 kg = 0 . 0216 m / s 2 . Since v i = 0 m/s, v f = a t t = v f a = 89 . 2 km / h . 0216 m / s 2 1000 m 1 km 1 h 3600 s = 1147 . 12 s . 002 10.0 points The horizontal surface on which the objects slide is frictionless. The acceleration of gravity is 9 . 8 m / s 2 . 1 kg 9 kg 4 kg F F r If F = 20 N and F r = 6 N, what is the magnitude of the force exerted on the block with mass 9 kg by the block with mass 4 kg? Correct answer: 10 N. Explanation: m 1 m 2 m 3 F F r Given : vector F = +20 N , vector F r = 6 N , m 1 = 1 kg , m 2 = 9 kg , m 3 = 4 kg , and g = 9 . 8 m / s 2 . Note: F is acting on the combined mass of the three blocks, resulting in a common acceleration after accounting for friction. m 1 F 21 F m 2 F 32 F 12 m 3 F r F 23 Let F , F r , F 32 represent the force exerted on the system from the right, from the left, and the force exerted on m 2 by m 3 , respec- tively. Note: vector F 21 = vector F 12 and vector F 32 = vector F 23 , and bardbl vector F 21 bardbl = bardbl vector F 12 bardbl and bardbl vector F 32 bardbl = bardbl vector F 23 bardbl , where bardbl vector F bardbl F is the magnitude of vector F ....
View Full Document

This note was uploaded on 11/29/2011 for the course PHY 302K taught by Professor Kaplunovsky during the Spring '08 term at University of Texas at Austin.

Page1 / 5

Practice Questions for Exam 1-solutions - markowitz...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online