Final answer:
In a physics problem about inelastic collisions, two spheres collide resulting in a shared velocity post-collision, and calculation of kinetic energy lost is required, using the mass of the second sphere being equal to the first (3 kg).
Step-by-step explanation:
The question involves concepts from Physics, particularly dealing with inelastic collisions in one dimension. Given a 3 kg sphere moving and colliding inelastically with another sphere of the same mass at rest, we calculate outcomes such as the common velocity after the collision and the kinetic energy lost.
For part (a), assuming a perfectly inelastic collision, the velocity after the impact for both spheres would be 15 m/s in the initial direction of the moving sphere. For part (b), to calculate the kinetic energy lost, one would use the formula for kinetic energy (KE = 0.5 * m * v^2) before and after the collision.
The mass of the second sphere is given as 3 kg, which is the same as the first one. The kinetic energy lost can be computed using the difference in kinetic energy pre- and post-collision.