Work and Energy...

If the mass of the moving object is decreased 1/4 of its mass and its velocity is increased to twice its previous velocity, what will be the kinetic energy of the object from the following?

The energy possessed by a body due to its change in position or shape is called:

A man carries a load on his head through a distance of 5 m. The maximum amount of work is done when he

Let us suppose there are two balls of an equal mass shape and size. We apply an equal force on both. Then work done by the force will be:

An object is thrown vertically upwards. As it rise, its total energy

A body of mass $$m$$ kg is lifted by a man to a height of one metre in $$30$$ sec.Another man lifts the same mass to the same height in $$60$$ sec. The work done by them are in the ratio

The $$P.E.$$ and $$K.E.$$ of a helicopter flying horizontally at a height $$400\ m$$ are in the ratio $$5:2$$. The velocity of the helicopter is:

A staircase has $$40$$ steps each of width $$35cm$$ and height $$25cm$$.A boy of mass $$20kg$$ ascends the staircase.The work done by him is  (taken $$g=10ms^{-2})$$

A particle is acted upon by a force F which varies with position x as shown in the figure. If the particle at $$x=0$$ has the kinetic energy of $$25$$ J, then the kinetic energy of the particle at $$x=16$$m is?

An object of mass $$5 \ kg$$  falls from rest through a vertical distance of $$20 \ m$$ and reaches a velocity of $$10 \ m/s$$. How much work is done by the push of the air on the object?