Final answer:
The work done by the child pulling a sled horizontally across an icy surface with no friction is 250 J.
Step-by-step explanation:
The question involves calculating the work done by a child pulling a sled, which is a physics concept. Using the formula W = Fd cosθ, where W is work, F is the force, d is displacement, and θ is the angle between the force and displacement, we can determine the work done by the child. In this scenario, since there is no friction on the icy sidewalk and the force is applied horizontally (cos0° = 1), the angle θ is 0°. Therefore, the work done by the child is calculated as (50 N)(5 m)(cos0°), which equals 250 J.