Advertisements
Advertisements
प्रश्न
State the empirical laws of static and kinetic friction.
Advertisements
उत्तर
The empirical laws of friction are:
- Friction is independent of the surface of contact.
- The coefficient of kinetic friction is less than the coefficient of static friction.
- The direction of frictional force is always opposite to the motion of one body over the other.
- Frictional force always acts on the object parallel to the surface on which the object is placed,
- The magnitude of frictional force between any two bodies in contact is directly proportional to the normal reaction between them.
APPEARS IN
संबंधित प्रश्न
Suggest a few methods to reduce friction.
Briefly explain ‘rolling friction.'
A block of mass 20 kg is sliding on a surface is inclined at an angle of 45° with the horizontal. What will be the acceleration of the block if the coefficient of kinetic friction between the block and the surface is 0.7?
If a body of mass m is moving on a rough horizontal surface of coefficient of kinetic friction µ, the net resultant force exerted by surface on the body is ______.
A block of mass m is pulled by a constant power P placed on a rough horizontal plane. The friction co-efficient between the block and the surface is µ. Maximum velocity of the block will be:
The minimum radius of a circle along which a cyclist can ride with a velocity 18 km/hr if the coefficient of friction between the tyres and the road is µ = 0.5, is ______ (Take g = 10 m/s2)
The coefficient of static friction between a car's tires and a level road is 0.80. If the car is to be stopped in a maximum time of 3.0 s, its speed cannot exceed.
A block of mass 10 kg starts sliding on a surface with an initial velocity of 9.8 ms-1. The coefficient of friction between the surface and bock is 0.5. The distance covered by the block before coming to rest is ______.
[use g = 9.8 ms-2]
There are two inclined surfaces of equal length (L) and same angle of inclination 45° with the horizontal. One of them is rough and the other is perfectly smooth. A given body takes 2 times as much time to slide down, on rough surface than on the smooth surface. The coefficient of kinetic friction (μ) between the object and the rough surface is close to ______.
A horizontal force 10 N is applied to a block A as shown in figure. The mass of blocks A and B are 2 kg and 3 kg, respectively. The blocks slide over a frictionless surface. The force exerted by block A on block B is:

