A ball of mass 'm', moving with uniform speed, collides elastically with another
stationary ball. The incident ball will lose maximum kinetic energy when the mass of the stationary ball is $\_\_\_\_\_\_$ m.

When the masses of the two balls are equal, the incident ball loses the most K.E. after an elastic collision between moving and stationary balls.
Therefore, when the mass of the stationary object is m, the incident ball will lose the most kinetic energy.

Hence the correct answer is 1.