Final answer:
To lift a 1275 lb object 45.0 ft with a motor that produces 15.0 hp, it would take approximately 1.5 hours. therefore correct option is A
Step-by-step explanation:
To find the time required to lift the object, we need to calculate the work done and divide it by the power output of the motor.
Work is calculated as the product of force and distance, which in this case is the weight of the object (1275 lb) multiplied by the height (45.0 ft). The force is equal to the weight, which can be calculated by multiplying the mass (1275 lb) by the acceleration due to gravity (32.2 ft/s²).
Using this information, we can calculate the work done and then divide it by the power output of the motor (15.0 hp) to find the time required.
Now let's calculate:
Force = mass x acceleration due to gravity
= 1275 lb x 32.2 ft/s²
Work = force x distance
= (1275 lb x 32.2 ft/s²) x 45.0 ft
Time = work / power output
= (1275 lb x 32.2 ft/s² x 45.0 ft) / 15.0 hp
Converting the units, we get:
Time = (1275 lb x 32.2 ft/s² x 45.0 ft) / (15.0 hp x 746 W/hp)
Simplifying the calculation gives:
Time = 1.5 hours