ME 232 Homework Problems

Problem 2/167 Page 85, Engineering Mechanics - Dynamics, Meriam and Kraige, 4th Edition

Given: Velocity of a particle, the magnitude of the acceleration of the particle, and the angle between the acceleration and the velocity.

Find: The radius of curvature of the path and the rate of change of speed of the particle.

Parameter values:

v = 4 i - 2 j - 1 k m/s = Velocity vector
q = 20 degrees = Angle between velocity and acceleration vectors
A = 8 m/s2 = Magnitude of acceleration.

The rate of change of the speed is the tangent component of the acceleration.
dv/dt = at = A cos(q) = 7.52 m/s2

The normal acceleration is related to the radius of curvature.

an = v2/r

an = A sin(q) = 2.74 m/s2

v2 = vx2 + vy2 + vz2 = (16 + 4 + 1) (m/s)2 = 21 (m/s)2

r = v2/an = 21 (m/s)2 / 2.74 m/s2 = 7.67 m