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In this chapter, you have completed: 45 concepts More than 35 doubts, important facts, points to remember etc. More than 90 number of Questions, Solutions, and Examples In this chapter, firstly you read "Laws of motion” and then moved to “applications of Laws of motion”. Apart from this there are certain tips for you which will be helpful for you to develop a lot of interest in this chapter....
The direction of centripetal acceleration and the tangential acceleration is always perpendicular in non-uniform circular motion.
A concave surface is a surface that curves inward. while A convex surface is a surface that curves outward.
Friction between the sliding surfaces of two objects can be reduced by making the surfaces in contact smooth by polishing them. Sliding friction between the moving parts of vehicles can be reduced by using oil, grease or graphite.
When the body is moving with some acceleration, then the frictional force acting on the body is kinetic friction.
For example - For a circular surface, the direction of the normal force exerted by circular surface is perpendicular to the tangent of that point. So, that direction will meet the center of that circular surface
The angle of repose is defined as the angle of the inclined plane with horizontal such that the body is placed on it just begins to slide.
The angle between the normal reaction and resultant contact force is called the angle of friction(Ó¨).
Static friction is a variable force and it changes itself according to the applied force so that's why static friction is a self-adjusting force.
The term rolling friction refers to the resistance created by an object rolling across a surface. Examples of rolling friction can help you to understand this concept. You will understand this well in Rotation chapter.
Yes, sometimes friction can act in the direction of motion. For example:- A car accelerates on the road only because the frictional force on the car due to the road drives it, i.e., the car would not accelerate if tires did not push against the road and the road pushed against tires. The force that accelerates your car is the static friction against your tires in the direction you are accelerating.
Where  and i.e Higher the mass of gun lesser will be recoil velocity  
Weightlessness is the condition when apparent weight = 0. You will study this in detail in the chapter of gravitation
When Lift is moving up with a = g then    Apparent weight = 2 (Actual weight) So the ratio of  Apparent weight to  Actual weight of the body is equal to 2
Generally, We assume spring is massless. And Force at every point in a massless spring remains the same. If the mass of the spring is also given then Force at every point in spring will not be same.
As For three blocks, (two are hanging and one is at the rest on the smooth horizontal table) acceleration of the system So a=0    
In the above figure 1) If pulled slowly string will break from point A. 2) If pulled with a sudden jerk then it will experience Tension & due to inertia of rest of mass(load) F will  not be transmitted to point A,      so it will break  from B point
No As    here if we interchange the position of two masses then the acceleration of system will remain the same.