14. Exercises

From Mechanics

(Difference between revisions)
Jump to: navigation, search
Line 32: Line 32:
</div>{{#NAVCONTENT:Answer|Answer 14.2|Solution|Solution 14.2}}
</div>{{#NAVCONTENT:Answer|Answer 14.2|Solution|Solution 14.2}}
 +
 +
 +
 +
 +
===Exercise 14.3===
 +
<div class="ovning">
 +
 +
A uniform beam has mass 20 kg and length 6 m. It rests on two supports that are 1.5 m from each end of the beam. A concrete block of mass 5 kg is placed at a point on the beam at a distance of 2.5 m from one end. Find the magnitude of the reaction forces exerted on the beam by the two supports.
 +
 +
 +
</div>{{#NAVCONTENT:Answer|Answer 14.3|Solution|Solution 14.3}}

Revision as of 18:07, 10 November 2009

       Theory          Exercises      


Exercise14.1

A uniform beam of mass 20 kg and length 3m rests on two supports as shown below.

Image:E14.1.GIF

(a) Find the reaction force exerted by each support.

(b) Find the greatest mass that can be placed at the left hand end of the beam.



Exercise 14.2

A plank has length 6 m. The plank is placed on a quayside with its mid-point at the edge of the quay, so that half of the plank sticks out over the water. A rock of mass m kg, which should be modeled as a particle is placed at the end of the plank which is on the ground. A person of mass 60 kg walks on the part of plank that is over the water. When the person is 1 m from the end the plank is on the point of tipping. Find m.

Image:E14.2.GIF



Exercise 14.3

A uniform beam has mass 20 kg and length 6 m. It rests on two supports that are 1.5 m from each end of the beam. A concrete block of mass 5 kg is placed at a point on the beam at a distance of 2.5 m from one end. Find the magnitude of the reaction forces exerted on the beam by the two supports.