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: lai (yl8859) HW10 Ross (15200) 1 This print-out should have 7 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A 3 . 6 kg block moving along the x axis is acted upon by a single horizontal force that varies with the blocks position according to the equation F x = ax 2 + b, where a = 4 N / m 2 , and b =- 1 . 8 N. At 1 . 7 m, the block is moving to the right with a speed of 3 . 5 m / s. Determine the speed of the block at 2 . 6 m. Correct answer: 4 . 55302 m / s. Explanation: The change in the potential energy is U = U f- U i =- integraldisplay f i F x dx =- integraldisplay f i ( ax 2 + b ) dx = parenleftbigg 1 3 ax 3 i + bx i parenrightbigg- parenleftbigg 1 3 ax 3 f + bx f parenrightbigg = 15 . 264 J . From conservation of energy, K i + U i- U f = K f or mv 2 i 2 + U = mv 2 f 2 . Solving for v f , we have v f = radicalbigg v 2 i- 2 U m = radicalBigg (3 . 5 m / s) 2 + 2(15 . 264 J) 3...
View Full Document
- Winter '08