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Unformatted text preview: schroeder (cs39963) – Resource 5: Newton’s Laws of Motion – balasubramanya – (1401310) 1 This print-out should have 60 questions. Multiple-choice questions may continue on the next column or page – Fnd all choices before answering. 001 10.0 points One Newton is the force 1. that gives a 1 g body an acceleration of 1 cm/s 2 . 2. of gravity on a 1 g body. 3. that gives a 1 kg body an acceleration of 1 m/s 2 . correct 4. that gives a 1 kg body an acceleration of 9.8 m/s 2 . 5. of gravity on a 1 kg body. Explanation: One Newton is a kg · m / sec 2 , so such a force acting on a 1 kg body gives a 1 m/sec 2 acceleration 002 (part 1 of 2) 10.0 points A dog pulls on a pillow with a force of 6 . 4 N at an angle of 37 . 9 ◦ above the horizontal a) What is the x component of this force? Correct answer: 5 . 05014 N. Explanation: F = 6 . 4 N F y F x 37 . 9 ◦ Note: ±igure is not drawn to scale. Basic Concept: F x = F cos θ Given: F = 6 . 4 N θ = 37 . 9 ◦ Solution: F x = (6 . 4 N) cos37 . 9 ◦ = 5 . 05014 N 003 (part 2 of 2) 10.0 points b) What is the y component of this force? Correct answer: 3 . 93143 N. Explanation: Basic Concept: F y = F sin θ Solution: F y = (6 . 4 N) sin37 . 9 ◦ = 3 . 93143 N 004 10.0 points A hockey puck slides across the ice at a con-stant speed. Which of the following is true? 1. The puck can be considered neither at rest nor in equilibrium. 2. The puck is at rest. 3. None of these 4. The puck is moving and thus not in equi-librium. 5. It is in equilibrium. correct Explanation: If the puck moves in a straight line with unchanging speed, the forces of friction are negligible. Then the net force is zero, and the puck can be considered to be in equilibrium. 005 (part 1 of 2) 10.0 points The wind exerts a force of 164 N North on a sailboat, while the water exerts a force of 41 N West on the sailboat. What is the magnitude of the net external force on the sailboat? Draw the vectors to scale on a graph to determine the answer. schroeder (cs39963) – Resource 5: Newton’s Laws of Motion – balasubramanya – (1401310) 2 Your answer must be within ± 5.0% Correct answer: 169 N. Explanation: 164 N 41 N 169 N Scale: 100 m 14 ◦ F x = F water = − 41 N F y = F wind = 164 N Taking a ruler to measure the resultant, we Fnd that it is 1 . 7 times the length of the scale, so v v v v F v v v = 1 . 7 × (100 N) ≈ 169 N 006 (part 2 of 2) 10.0 points How many degrees west of north is this net external force directed? Your answer must be within ± 8.0% Correct answer: 14 ◦ . Explanation: Using a protractor, we Fnd that θ = 14 ◦ west of north. 007 (part 1 of 2) 10.0 points Consider the mass and a frictionless ramp shown in the Fgure. The mass is pushed upward with some initial velocity. Because of the in±uence of gravity it moves upward and reaches the highest point. It then turns around and moves downward. Starting from point A , along the way it passes consecutively the points B , C , D and E at equal time intervals. Denote by Δ intervals....
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This note was uploaded on 12/02/2010 for the course PHYS 1401 taught by Professor Staff during the Fall '08 term at Texas A&M University, Corpus Christi.
- Fall '08