Four points (x_1, y₁), (x_2, y₂), (x_3, y₃) and (x₄, y₄) such that Σ(x_i² + y_i²) ₁x₃ + x₂x₄ + y₁y₂ + y₃y₄)

Then these points are vertices of -
(A) Parallelogram (B) Rectangle
(C) Square (D) Rhombus

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

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