The first scientist to be credited for postulating that Earth circled the Sun was Aristotle. Copernicus. Galileo. Newton A block pulled to the left with 15 N and to the right with 5 N at the same time experiences a net force of 5N 10 N 15N 20 N

## Step1<br />The first question is about the history of astronomy. The scientist who first proposed that the Earth revolves around the Sun is Nicolaus Copernicus. This theory is known as the heliocentric model.<br /><br />## Step2<br />The second question is about the concept of net force in physics. When two forces are acting on an object in opposite directions, the net force is the difference between the two forces. In this case, the block is being pulled to the left with a force of 15 N and to the right with a force of 5 N. <br /><br />## Step3<br />To find the net force, we subtract the smaller force from the larger one. This gives us the net force acting on the block.