Applied Dynamics
MoreNew
adhw3e.docx
University of Toledo Name________________
College of Engineering e-mail_________________
Department of Engineering Technology
MET 3400 Applied Dynamics HW3 J. Kamm
Partial credit will be given so put down something intelligent even if you can’t get an answer
1) a) The lady below is pulling on a 200 lb door that is on rollers and has a center of gravity at the geometric center. If the door is slid opened at a constant acceleration and it takes 5 seconds to move it 12 feet, what is the acceleration?
b) From the above, what is the force that the lady is exerting during the pull?
c) What are the vertical reaction forces on each roller during the pull. (Hint: RL = RR = 100 lb if the door is not being pulled.)
d) What would the reaction forces be if the door handle was located at a height of six feet (along the line of the CG) and being pulled with the force of Part b?
12 ft
6’ 6’
3’
2) A bobble-doll sits on the dash of a small pleasure boat. The tiger head has mass = 100 grams and vibrates vertically in a spring with a constant 4 kN/m.
a) what is the natural frequency of the bobble?
b) In rough seas the boat is moving up and down on the waves according to the equation
= .7 sin (.2t)
What is the equation for the vibration of the bobble head including the forced vibration of the boat?
c) Draw a Spectrum Diagram of the bobble-head vibration
Name _____________________
3)
A forty pound tool box (1 ft wide x 2.5 ft high) is in the bed of a pickup truck. The coefficient of friction between the toolbox and bed is .6. What is the minimum acceleration that the pick-up can have without having the toolbox fall over?
4) The ‘retractable power cord’ mechanism on a vacuum cleaner consists of a four inch diameter pulley connected to a torsional spring. Once tripped, the angular acceleration profile looks like:
How long does this mechanism take to wind a 12 ft cord???
