MAEKE 2 72-01 DYNAMICS FALL 2009

MID-TERM EXAM NAME: SOLO rmN Closed book, notes, and references. 80 minutes. BOX ALL ANSWERS.

ALL PROBLEMS ARE WEIGHTED EQUALLY (20ptslea).

1 .) At any instant the horizontal position of a weather balloon is defined by x = 8t ft where t is in seconds. If the equation of the path is y = x2/10, determine:

a.) The velocity and acceleration vectors in Cartesian coordinates. b.) The velocity and acceleration vectors at t = 2 s. c.) The magnitude of the acceleration at t = 2 s.

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MAE/CE 2 72 - MID-TERM EXAM NAME:

2.) A spring of stiffness k = 500 N/m is mounted against a 10-kg block. The spring is uncompressed and the block is at rest at x = 0. If the block is subjected to the force F = 500 N as shown, using Newton's 2"d Law and appropriate kinematics, determine:

a.) The velocity of the block as a function of the position x. b.) The velocity of the block at x = 0.5 m.

(A FREE BODY DIAGRAM MUST BE INCLUDED FOR FULL CREDIT)

MAE/CE 2 72 - MID-TERM EXAM NAME:

3.) Two small balls, each of 1 -1b weight hang from strings of length L = 3 ft. The left ball is released from rest when 0 = 35". The coefficient of restitution of the impact is e = 0.9. Determine:

a.) The maximum angle through which the right ball will swing (in degrees).

M A E/CE 2 72 - MID-TERM E M M NAME:

w ) The 26-in drum rotates about a horizontal axis with a constant angular velocity of = 7.5 radls. The small block has no motion relative to the drum surface as it

passes the bottom position 8 = 0. If the block is observed to slip as it reaches 8 = 50, using normal and tangential components, determine:

a) The coefficient of static fkiction, p,, between the block and drum.

(A FREE BODY DIAGRAM MUSTBE INCLUDED FOR FULL CREDIT)