Final answer:
To keep the wheely bin moving at a constant velocity of 1.5m/s against a frictional force of 20N, the horizontal force also needs to be 20N to counteract the friction. Therefore, the answer is B) 20N.
Step-by-step explanation:
The question is pertaining to a physics concept known as Newton’s second law of motion, which states that the force required to move an object at a constant velocity is equal to the frictional force opposed to its motion. Considering a wheely bin is moved at a steady speed along a horizontal path against a known frictional force of 20N, it implies that the horizontal force applied must be equal to the frictional force to maintain the constant speed, in accordance to Newton's first law, which says that an object in motion will stay in motion with a constant velocity unless a net force acts upon it.
To maintain the wheely bin moving at a constant 1.5m/s, we do not need to accelerate it, and therefore, the force we need to apply is equal to the opposing frictional force. The frictional force is given as 20N, so the horizontal force needed to apply will also be 20N. Therefore, the answer is B) 20N.