Cork Institute of Technology
Higher Certificate in Engineering in Mechanical Engineering – Award
(National Certificate in Engineering in Mechanical Engineering – Award)
(NFQ – Level 6)
Autumn 2005
Mechanical Technology - Mechanics
(Time: 3 Hours)
Instructions
Answer FIVE questions;
TWO questions from Section A, TWO from
Section B and any ONE other question.
Use separate answer books for each Section.
All questions carry equal marks.
Examiners: Mr. J. M. Brady
Mr. J. Connolly
Mr. R. Simpson
Section A – Mechanics of Machines
Q1. A 12 tonne wagon is moving at a velocity of 7.5 m/sec, travelling against a track
resistance of 100 N/tonne.
(a) Using the ‘Work-Energy’ equation, or any method, calculate its velocity after travelling a
further 120 m. (10 marks)
The 12 tonne wagon then strikes a 6 tonne wagon moving at a velocity of 4 m/sec in the
same direction.
(b) Using the Principle of Conservation of Momentum, calculate the velocity of the 6 tonne
wagon immediately after impact, if the 12 tonne wagon moves on immediately at a
velocity of 2.5 m/sec in the same direction as before. (10 marks)
Q2. (a) Describe with the aid of a sketch, the three main stages into which the operation of ‘pile
driving’ may be divided. When making calculations concerning the operation of ‘pile
driving’, state the principles of: energy; momentum; and work; which can be applied
during each stage. (12 marks)
(b) A pile driving hammer of mass 0.6 tonne falls 2.5 m from rest onto a pile of mass 150 kg.
The pile is driven 160 mm into the ground at each blow. Assuming there is no rebound
of the hammer on the pile, calculate:
(i) The common velocity of the hammer and pile into the ground just after impact.
(4 marks)
(ii) the average resisting force of the ground in bringing the pile and driver to rest.
(4 marks)
