This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: ghei (mg42382) – HW 11 – opyrchal – (11130) 1 This printout should have 9 questions. Multiplechoice questions may continue on the next column or page – find all choices before answering. 001 (part 1 of 3) 10.0 points A 1096 N uniform boom of length ℓ is sup ported by a cable, as shown. The boom is pivoted at the bottom, the cable is attached a distance 3 4 ℓ from the pivot, and a 3138 N weight hangs from the boom’s top. F T 3138 N 24 ◦ 66 ◦ Find the force F T applied by the supporting cable. Correct answer: 1998 . 98 N. Explanation: Let : W b = 1096 N , W m = 3138 N , θ b = 66 ◦ , and θ t = 24 ◦ . Applying the second (rotational) condition of equilibrium (with axis of rotation at the base of the beam and beam length ℓ ), τ net = F T parenleftbigg 3 4 ℓ parenrightbiggW b parenleftbigg ℓ 2 parenrightbigg cos θ bW m ℓ cos θ b = 0 . 3 F T 2 W b cos θ b 4 W m cos θ b = 0 F T = (2 W b + 4 W m ) cos θ b 3 = [2 (1096 N) + 4 (3138 N)] cos 66 ◦ 3 = 1998 . 98 N . 002 (part 2 of 3) 10.0 points Find the horizontal component of the reaction force on the bottom of the boom. Correct answer: 1826 . 15 N. Explanation: Applying the first (translational) condition of equilibrium horizontally, F x = R x,base F T cos θ t = 0 R x,base = F T cos θ t = (1998 . 98 N) cos24 ◦ = 1826 . 15 N . 003 (part 3 of 3) 10.0 points Find the vertical component of the reaction force on the bottom of the boom. Correct answer: 3420 . 94 N. Explanation: Applying the first (translational) condition of equilibrium vertically, F y = R y,base + F T sin θ tW mW b = 0 R y,base = W m + W b F T sin θ t = 1096 N + 3138 N (1998 . 98 N) sin24 ◦ = 3420 . 94 N . 004 10.0 points A light string has its ends tied to two walls separated by a distance equal to fiveeighths the length of the string as shown in the figure....
View
Full
Document
This note was uploaded on 05/02/2011 for the course PHYSICS 111 taught by Professor Wang during the Spring '09 term at NJIT.
 Spring '09
 WANG
 Physics

Click to edit the document details