Which of the following statements about friction is NOT correct?
The force of kinetic friction is less than the force of static friction
The force of kinetic friction between two surfaces is independent of the areas in contact provided the normal reaction is unchanged
The force of rolling friction between two surfaces is less than the force of sliding friction
The angle of friction is the angle between the normal reaction and the force of friction
Friction may be reduced by lubrication
Correct answer is D
- Static Friction is friction which is experienced when an object is placed on a surface. And, Kinetic friction is due to the movement of an object on a surface.
- Static friction is greater than kinetic friction because there are more forces at work keeping an object stationary than there are forces working to resist an object once it is in motion.
- Rolling friction is the weakest type of friction, static being the strongest. The frictional force depends on the area of contact between the two bodies. As the area of contact is less in rolling friction than the sliding friction, so rolling friction is weaker than sliding friction.
8
3
2
\(\frac{1}{2}\)
\(\frac{1}{3}\)
Correct answer is B
\(\lambda_1\) = 4L1 and \(\lambda_2\) = -L1
F\(\lambda\) = velocity
F1 x \(\lambda_1\) = F2 x
\(\lambda_2\) ; F1 x 4\(\lambda_1\) = F2 x -\(\lambda_2\)
= \(\frac{F_2}{F_1}\) = 3
\(\frac{5}{9}\)\(\Omega\) in parallel
\(\frac{9}{5}\)\(\Omega\) in series
45\(\Omega\) in parallel
45\(\Omega\) in series
\(\frac{9}{5}\)\(\Omega\) in parallel
Correct answer is A
Given Data:
I\(_g\) = 100ma = 0.1A
R\(_g\)=5
where I\(_s\) = I - I\(_g\) → 1 - 0.1
I\(_s\) = 0.9
I\(_g\)R\(_g\) = I\(_s\)R\(_s\)
0.1 * 5 = 0.9 * R\(_s\)
R\(_s\) = \(\frac{0.1 * 5}{0.9}\)
R\(_s\) = \(\frac{5}{9}\)
i only
ii only
i and ii
ii and iii
iii only
Correct answer is E
No explanation has been provided for this answer.
i and ii
i and iii
ii and iv
ii and iii
i, ii and iii
Correct answer is D
No explanation has been provided for this answer.