Problem 2.51

Problem 2.51 - Problem 2.51[Difficulty 4 Ff = A x V a M g...

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

Problem 2.51 [Difficulty: 4] F f τ A = x, V, a Mg Given: Data on the block and incline Find: Initial acceleration; formula for speed of block; plot; find speed after 0.1 s. Find oil viscosity if speed is 0.3 m/s after 0.1 s Solution: Given data M5 k g = A 0.1 m () 2 = d 0.2 mm = θ 30 deg = From Fig. A.2 μ 0.4 Ns m 2 = Applying Newton's 2nd law to initial instant (no friction) Ma sin θ F f = sin θ = so a init g sin θ = 9.81 m s 2 sin 30 deg × = a init 4.9 m s 2 = Applying Newton's 2nd law at any instant sin θ F f = and F f τ A = μ du dy A = μ V d A = so M dV dt = sin θ μ A d V = Separating variables dV g sin θ μ A Md V dt = Integrating and using limits μ A ln 1 μ A d sin θ V t = or Vt d sin θ μ A 1e μ A t = At t = 0.1 s V5 k g 9.81 × m s 2 0.0002 × m sin 30 deg m 2 0.4 N s 0.1 m 2 × 2 kg m × 0.4 0.01

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.

This note was uploaded on 10/19/2011 for the course EGN 3353C taught by Professor Lear during the Fall '07 term at University of Florida.

Page1 / 2

Problem 2.51 - Problem 2.51[Difficulty 4 Ff = A x V a M g...

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

View Full Document
Ask a homework question - tutors are online