50) When the leading edges of the teeth are not parallel to the axis of rotaton, but are set at an angle so that can be meshed in parallel or crossed orientations, they are called
Helical gears
Related KPCL AE Mechanical Question Papers - 2015 with Answer Key
Dynamic friction
Static Friction The friction experienced by a body, when it is at rest is known as static friction.
Dynamic Friction The friction experienced by a body, when it is in motion is called dynamic friction. Dynamic friction is also called as kinetic friction.
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Elastic bodies: The bodies which rebound after impact are called elastic bodies.
The impact between two rubber spheres is an elastic impact.
Inelastic bodies: The bodies which does not rebound at all after its impact are called inelastic bodies.
The impact between two lead spheres or two clay spheres is approximately an inelastic impact.
Coefficient of restitution is defined as the ratio of Relative velocity after impact to Relative velocity before impact. Coefficient of restitution is denoted by 'e'.
e = 0, For perfectly inelastic bodies .
e = 1, For perfectly elastic bodies.
0>e>1,(value of e lies between zero and one) For bodies neither perfectly inelastic nor perfectly elastic.
Dynamic friction is always less than static friction
Static Friction The friction experienced by a body, when it is at rest is known as static friction.
Dynamic Friction The friction experienced by a body, when it is in motion is called dynamic friction. Dynamic friction is also called as kinetic friction.
Dynamic friction always less than static friction.
The ratio of static friction to dynamic friction is always greater than one.
