According to the laws of dry friction, the frictional force between two surfaces is independent of the area of contact as long as the normal reaction force and the nature of the materials in contact remain constant. This means that the frictional force is not affected by how much area of the surfaces is in contact, which makes option (b) incorrect.
Which of the following statements about friction is correct?
A small ring Z carries vertical load A of mass 27.3 kg by two strings ZX and ZY. String ZY carries a load B at its free end through a frictionless pulley. Find the value of B (rounded to nearest integer), if the string is stable at the configuration shown in fig.
As shown in the figure, the plane, having a mass of 8000 kg, is hoisted back until θ = 60 and then the pull-back cable AC is released when the plane is at rest. Determine the speed of the plane just before it crashes into the ground at θ =30 . (Neglect the size of the plane and effect of lift caused by the wings during the motion, assume g = 10 )
The uniform link shown in the following figure has a mass of 12 kg. If the spring is un-stretched at θ = 0, determine the angle θ for stable equilibrium. Neglect the surface friction and assume g = 10 )
A satellite of mass 100 kg is attached centrally to the rocket stage of mass 900 kg using a separation system. In space the satellite is to be separated and ejected using 10 numbers of identical spring thrusters having same stroke of 30 mm. Assume springs are fully transferring the energy and angular body rate of the bodies are negligible after separation. What is the stiffness of the spring required to get the satellite axial relative velocity of 1 m/s.?
Three metal balls are suspended by three wires (a, b & c) of equal length arranged in sequence as shown in figure. The masses of the balls, starting at the top are 2 kg, 4kg and 3 kg. The wire diameters in the same order are 2 mm, 1.2 mm & 1 mm respectively. What is the correct order of increasing stresses in the wires?
If a solid cylinder, thin hollow cylinder and a sphere, all with same material and are having same outside diameter are allowed to roll down in same inclination without sliding. All surfaces are having same coefficient of friction. What is the order of the bodies reaching bottom
In an accident site, tyre marks shows that a car was travelling along straight level street skidded for a total distance of 23 m, after the brakes applied. The coefficient of friction between the tyre and road estimated to be 0.5, what was the probable speed of car when break applied.
The moment of resultant of concurrent forces with respect to a center in their plane is equal to the algebraic sum of the moments of components with respect to same center. This theorem is known as
