In a double-blind study, the participants don't know if they are in a control group or treatment group, and the experimenters also do not know if they participants are in a control group or treatment group. True
False

True

Step-by-step explanation:

Double blind means both sides are unaware of the groups

The work done is 4386.6 J.

Step-by-step explanation:

The work is given by:

Where:

F: is the applied force = 42 pounds

d: is the displacement = 85 feet  

Since the force is applied at an angle (θ) of 25° with the horizontal we have:

Therefore, the work done is 4386.6 J.

I hope it helps you!