Param Himalaya - परम हिमालय

NCERT Solution Class 11 Physics Chapter 5 Work, Energy and Power - Param Himalaya  5.1 The sign of work done by a force on a body is important to understand. State carefully. if the following quantities are positive or negative: (a) work done by a man in lifting a bucket out of a well by means of a rope tied to the bucket. (b) work done by gravitational force in the above case, (c) work done by friction on a body sliding down an inclined plane, (d) work done by an applied force on a body moving on a rough horizontal plane with uniform velocity, (e) work done by the resistive force of air on a vibrating pendulum in bringing it to rest. Solution :  (a) Positive: The man applies force upwards, and the bucket moves upwards. Force and displacement are in the same direction, so the work done is positive. (b) Negative: Gravitational force acts downwards, while the bucket moves upwards. Force and displacement are in opposite directions, so the work done is negative. (c) Negative: Fric...

NCERT Solution Class 11 Physics Chapter 4 Laws of Motion- Param Himalaya 4.1 Give the magnitude and direction of the net force acting on (a) a drop of rain falling down with a constant speed, (b) a cork of mass 10 g floating on water, (c) a kite skillfully held stationary in the sky, (d) a car moving with a constant velocity of 30 km/h on a rough road, (e) a high-speed electron in space far from all material objects, and free of electric and magnetic fields. Solution:  (a) Raindrop falling with constant speed:  * Magnitude: 0 N  * Direction: No direction (since the net force is zero) When an object moves with constant speed, its acceleration is zero. According to Newton's second law (F = ma), if acceleration is zero, the net force acting on the object is also zero. (b) Cork floating on water:  * Magnitude: 0 N  * Direction: No direction (since the net force is zero) The cork is in equilibrium, meaning the upward buoyant force from the water exactly balances the ...