Final answer:
The kinetic energy a 5 kg block has at the bottom of a frictionless 10° incline after sliding down from a height of 0.8 m is calculated using the conservation of energy. It will have the same kinetic energy as its initial potential energy, which is 39.2 J, not matching the provided options.
Step-by-step explanation:
The question asks how much kinetic energy a block of mass 5 kg has when it reaches the bottom of a frictionless inclined plane, starting from a height of 0.8 m. The kinetic energy of the block at the bottom is equivalent to the potential energy it had at the top, as energy is conserved in the absence of friction. The gravitational potential energy (PE) at the height of 0.8 m can be calculated using PE = mgh, where m is the mass, g is the acceleration due to gravity, and h is the height. Substituting the given values, PE = 5 kg × 9.8 m/s2 × 0.8 m = 39.2 J. Therefore, the kinetic energy (KE) at the bottom is also 39.2 J. However, since this value is not provided in the answer options, there may be a mistake in either the question or the answer choices.