Torque and Screw Jack
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www.jwjobs.net
R5
Code: R5 100305
B.Tech I Year (R05) Supplementary Examinations, May 2012
ENGINEERING MECHANICS
(Mechanical Engineering)
Time: 3 hours
Max Marks: 80
Answer any FIVE questions
All questions carry equal marks
*****
1 (a)
(b)
Define free body diagram, transmissibility of a force and resultant of a force.
Two identical rollers, each of weight 100 N, are supported by an inclined plane and a vertical wall as shown in figure 1. Assuming smooth surfaces, find the reactions induced at the points of support A, B and C.
Q
Q
D
L
C
B
W
U
Figure :1
2 (a)
(b)
R
O
A
T
N
Explain the principles of operation of a screw-jack with neat sketch.
Outside diameter of a square threaded spindle of a screw jack is 40 mm. The screw pitch is
10 mm. If the coefficient of friction between the screw and the nut is 0.15, neglecting friction between the nut and collar, determine
(i) Force required to be applied at the screw to raise a load of 2000 N
(ii) The efficiency of screw jack
(iii) Force required to be applied at pitch radius to lower the same load of 2000 N and
(iv) Efficiency while lowering the load.
J
3
An open belt drive connects two pulleys 120 cm and 40 cm diameter on parallel shafts 4 m apart. The maximum tension in the belt is 1855 N. The coefficient of friction is 0.3. The driver pulley of diameter 120 cm runs at 200 rpm. Calculate:
(i) The power transmitted.
(ii) Torque on each of the two shafts.
4
A steel ball of diameter 150 mm rests centrally over a concrete cube of size 150 mm.
Determine the center of gravity of the system, taking weight of concrete = 25,000 N/m2 and that of steel 80,000 N/m 2.
Contd. in Page 2
Page 1 of 2
www.jntuworld.com
www.jntuworld.com
www.jwjobs.net
R5
Code: R5 100305
5
(a)
(b)
6
(a)
(b)
7
(a)
(b)
8
Show that the moment of inertia of a thin circular ring of mass ‘M’ and mean radius
www.jwjobs.net
R5
Code: R5 100305
B.Tech I Year (R05) Supplementary Examinations, May 2012
ENGINEERING MECHANICS
(Mechanical Engineering)
Time: 3 hours
Max Marks: 80
Answer any FIVE questions
All questions carry equal marks
*****
1 (a)
(b)
Define free body diagram, transmissibility of a force and resultant of a force.
Two identical rollers, each of weight 100 N, are supported by an inclined plane and a vertical wall as shown in figure 1. Assuming smooth surfaces, find the reactions induced at the points of support A, B and C.
Q
Q
D
L
C
B
W
U
Figure :1
2 (a)
(b)
R
O
A
T
N
Explain the principles of operation of a screw-jack with neat sketch.
Outside diameter of a square threaded spindle of a screw jack is 40 mm. The screw pitch is
10 mm. If the coefficient of friction between the screw and the nut is 0.15, neglecting friction between the nut and collar, determine
(i) Force required to be applied at the screw to raise a load of 2000 N
(ii) The efficiency of screw jack
(iii) Force required to be applied at pitch radius to lower the same load of 2000 N and
(iv) Efficiency while lowering the load.
J
3
An open belt drive connects two pulleys 120 cm and 40 cm diameter on parallel shafts 4 m apart. The maximum tension in the belt is 1855 N. The coefficient of friction is 0.3. The driver pulley of diameter 120 cm runs at 200 rpm. Calculate:
(i) The power transmitted.
(ii) Torque on each of the two shafts.
4
A steel ball of diameter 150 mm rests centrally over a concrete cube of size 150 mm.
Determine the center of gravity of the system, taking weight of concrete = 25,000 N/m2 and that of steel 80,000 N/m 2.
Contd. in Page 2
Page 1 of 2
www.jntuworld.com
www.jntuworld.com
www.jwjobs.net
R5
Code: R5 100305
5
(a)
(b)
6
(a)
(b)
7
(a)
(b)
8
Show that the moment of inertia of a thin circular ring of mass ‘M’ and mean radius