The boat moves forward due to A. a forward thrust from the propeller that is greater than the backward force of the water current. B. a forward thrust from the propeller that is equal to the backward force of the water current. C. a backward thrust from the propeller against the water that is greater than the force of gravity. D. a backward thrust from the propeller against the water that is less than the force of gravity.

(B). a forward thrust from the propeller that is equal to the backward force of the water current.

Explanation:

A boat generates thrust when the propellers are turned to accelerate water forward. According to Newton's third law, the resulting thrust pushes the boat in the opposite direction (i.e. backward direction) which is equal in magnitude.

So, the boat moves forward due to a forward thrust from the propeller that is equal to the backward force of the water current.

Hence. option (B) is correct.

the amount of current in the coil