# S05s(3) - Physics 4A Name FINAL EXAM Chapters 1 14 Spring...

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

FINAL EXAM Chapters 1 - 14 Spring 2005 1 Name: Posting Code ____ ____ ____ (only if you want your grade posted on the web.) Solve the following problems in the space provided. Use the back of the page if needed. Each problem is worth 10 points. You must show your work in a logical fashion starting with the correctly applied physical principles shown on the last page. Your score will be maximized if your work is easy to follow because partial credit will be awarded. 1. A helicopter flying horizontally at 30.0m/s is 80.0m above the ground and plans to drop supplies to tsunami victims below. Find (a)the time before they are directly overhead that they must release the supplies so that they land near these victims and (b)the horizontal distance from where they release them to the point where they land. (a)Using the kinematic equation along the y-direction, y = y o + v oy t + 1 2 a y t 2 Plugging in the numbers, 0 = y o + 1 2 a y t 2 " t = # 2 y o a y = # 2(80.0) # 9.80 " t = 4.04 m / s . (a)Using the kinematic equation along the x-direction, x = x o + v ox t + 1 2 a x t 2 Plugging in the numbers, x = v ox t " x = (30.0)(4.04) " x = 121 m . 2. A 150g meterstick is suspended horizontally from a string at the 30cm mark that is wrapped over a pulley supporting a mass M. Two weights hang from the stick. One has a mass of 100g at the 80cm mark and the other is at the 5cm mark. Find the mass at the 5cm mark and the mass M needed to keep the meterstick in equilibrium. Applying the Second Law for Rotation about the origin, " # = I \$ % 25 Mg 45 mg 75 m 2 g = 0 Solving for M, M = 45 m + 75 m 2 25 = 45(150) + 75(100) 25 " M = 570 g . Applying the Second Law along the y-direction, " F y = ma y # Mg \$ mg \$ m 1 g \$ m 2 g = 0 Solving for m 1 , m 1 = M " m " m 2 = 570 " 150 " 100 # m 1 = 320 g . x y v o h x o = 0 x = ? v

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### Page1 / 5

S05s(3) - Physics 4A Name FINAL EXAM Chapters 1 14 Spring...

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

View Full Document
Ask a homework question - tutors are online