23-11 BioMechanics (BM)

MEHRAN UNIVERSITY OF ENGINEERING AND TECHNOLOGY, JAMSHORO. SECOND TERM FIRST YEAR (2ND TERM) B.E.(BIOMEDICAL) REGULAR EXAMINATION 2005 OF 05-BATCH. BIO-MECHANICS Dated: 23-11-2005. NOTE:

Time Allowed: 03 Hours.

Max:Marks-80

ATTEMPT ANY FIVE QUESTIONS. ALL QUESTIONS CARRY EQUAL MARKS. ‘R’ IS YOUR ROLL NUMBER. ASSUME YOUR OWN DATA WHERE NECESARRY.

Q.No. 01

Explain different systems of units used in the world and the Rules for proper use of them. Evaluate each of the following and express with S.I Units having approximate prefix. (a) [{(50+R) m N} {6 GN}] (b) [{(400+R) mm} {0.6 MN} 2] (c) [{(45+R) MN} 3 / {6 Gg}]

02 (a) What is force systems. (b) The block as shown in Fig.Q.No.2 is acted upon by its weight w=200lb, a horizontal force Q=600lb and the pressure P exerted by the inclined plane. The resultant R of these forces is up and parallel to the incline there by sliding the block up it. Determine P and R. 03 (a) What is parallelogram law. (b) Two horses an opposite banks of a canal pull a barge moving parallel to the banks by means of two horizontal ropes. The tensions in these ropes are 200 lb and 240lb while the angle between them is 60o. Find the resultant pull on the barge and the angle between each of the ropes and the sides of the canal. 04

What is meant by moment of a force? In figure.#.3, if the moment of P is (3600+X) ft-lb about C, find the moment of P about D and B. If the moment of F about B is (6000+X) ft-lb, find the moment of F about A and D. Find also the moment of force S, having value of 2000 lb and passing through C., about the points A,B,C and D points.

05 (a) Give formal procedure for drawing the F.B.D (Free body diagram). (b) Determine the reactions for the beam loaded as shown in Fig.Q.No.5. 06

(a) what do you understand by the coplanar forces. Four forces 50, 60, 70 and (X+20) lbs act on directions north to east, north to west, south to east and south to west respectively. Find the magnitude and directions of resultant. (b) Find the greatest and the least resultant of two forces with magnitude of (200+X) and (250+X) and their angles.

07

How would you distinguish between motion, when it is subjected to (a) constant acceleration and (b) variable acceleration? A stone is dropped from top of building 100 m high. Another stone is projected upward at the same time, from the foot of the building and meets the first stone at height of (18+X) m. Find the velocity with which the second stone is projected upwards.

08

What do you understand by the term “Energy”? A machinegun bullet of mass 20 gm is fired with a velocity and has K.E. of (200+X) kg-m., the bullet can penetrate 225 mm in a given target. If the same target is 10 cm thick, what will be velocity of the bullet with which it comes out target? Also determine the velocity of bullet, when it is fired with machine gun.

(See figures on Backside)

P

A

1’

S

D

B 1’

Fig. # 3

C

F