Gravitational force is a universal force. Every object in the universe attracts every other object in the universe gravitationally. Therefore gravitational force does pull the aeroplane towards the centre of the earth, but the force exerted by the engine of the plane makes it fly in the air.

When the effort arm is greater than the load arm, the lever acts as a force multiplier. The amount of force required to lift an object will decrease if the length of the effort arm increases or the length of the load arm decreases. Therefore Keshav should either increase the length of effort arm or decrease the length of load arm.

Every object in the universe attracts every other object in the universe gravitationally. Therefore gravity is a universal force.
For an object to experience gravitational force  it doesn't need to be in  contact, hence gravitational force is a non-contact force.

The gravitational force of Earth attracts eveything towards it centre. The Moon stays on orbit around Earth because of gravity. The apple and the book both fall because of gravity. A boat sails on water because wind applies a force on it which makes it move. 

Answer: Option A. ->

The lever shown in the question belongs to Class I i.e. fulcrum lies in the centre. Similar type of levers are exhibited by the see-saw and the plier, where the load and the effort are at the two ends whereas the fulcrum is present in the centre. 

Kinetic energy is the energy possessed by a body or an object because of it's motion.
Example: A ball rolling on the floor has kinetic energy because of its motion.

Slides have an inclined plane. An inclined plane is a simple machine used to lift heavy objects.

To pull out a nail using a hammer, the effort is applied on the handle and the hammer claw is used to pull out the nail, which is the load point.