# Modern gear tooth profile is given involute shape because

1.  this is very easy curve for manufacturing

2.  sliding does not takes place anywhere on meshing teeth

3.  involute is the only profile that gives conjugate action

4.  change in the center distance does not change gear ratio

4

change in the center distance does not change gear ratio

Explanation :
No Explanation available for this question

# Tooth interference in an external involute spur gear pair can be reduced by

1.  decreasing center distance between gears

2.  decreasing module

3.  decreasing pressure angle

4.   increasing number of teeth

4

increasing number of teeth

Explanation :
No Explanation available for this question

# In order to test the efficiency of reducer gear rain 1KW input was given at the input end at a speed of 1440 RPM and at the output end the measured torque was 56.36 N.m. If the ration of speed reduction in this unit is 10:1, the efficiency is about

1.  78%

2.  85%

3.   63%

4.   96%

4

85\%

Explanation :
No Explanation available for this question

# The expected life of a ball bearing subjected to a load of 9800N and working a 1000RPM. Is 3000 hours. What is the expected life of the same bearing for a similar load of 4900N and a speed of 2000rpm

1.  Unchanged

2.   12000 hours

3.  1500 hours

4.  6000 hours

4

12000 hours

Explanation :
No Explanation available for this question

# In order to test the efficiency of reducer gear rain 1KW input was given at the input end at a speed of 1440 RPM and at the output end the measured torque was 56.36 N.m. If the ration of speed reduction in this unit is 10:1, the efficiency is about

1.  78%

2.  85%

3.   63%

4.   96%

4

85\%

Explanation :
No Explanation available for this question

# If the load on a ball bearing is reduced to half, the life of the ball bearing will

1.  increases 8 times

2.  increases 4 times

3.  increases 2 times

4.  not change

4

increases 8 times

Explanation :
No Explanation available for this question

1.  a-u, b-q, c-r, d-t

2.  a-v, b-s, c-r, d-t

3.  a-u, b-s, c-r, d-v

4.  a-u, b-s, c-r, d-v

4

a-u, b-q, c-r, d-t

Explanation :
No Explanation available for this question

# Spherical roller bearings are normally used

3.  when there is less radial loa

4.  to compensate for angular misalignment

4

to compensate for angular misalignment

Explanation :
No Explanation available for this question

# Two identical ball bearings P and Q are operating at loads 30kN and 45kN respectively. The ratio of the life of bearing P to the life of bearing Q is

1.  81/16

2.  27/8

3.  9/4

4.  3/2

4

27/8

Explanation :
No Explanation available for this question

# Starting friction is low in

1.  hydrostatic lubrication

2.  hydrodynamic lubrication

3.  mixed (or semi-fluid) lubrication

4.  boundary lubrication

4