Final answer:
To calculate the time it takes to mow the yard, we divide the work done by the power used, which results in approximately 90 seconds.
Step-by-step explanation:
To determine the time it takes to mow the yard using the given work and power, we use the relationship between power, work, and time. Power is the rate of doing work, defined by the equation Power (P) = Work (W) / Time (t). Solving for time gives us Time (t) = Work (W) / Power (P). Using the provided values, we get:
t = 145 J / 1.61 W
t = 90.06 seconds. Therefore, the closest answer is:
A. 90 seconds