Answer:
Earth would continue moving by uniform motion, with constant velocity, in a straight line
Step-by-step explanation:
The question can be answered by using Newton's first law of motion, also known as law of inertia, which states that:
"an object keeps its state of rest or of uniform motion in a straight line unless acted upon by an external net force different from zero"
This means that if there are no forces acting on an object, the object stays at rest (if it was not moving previously) or it continues moving with same velocity (if it was already moving) in a straight line.
In this problem, the Earth is initially moving around the Sun, with a certain tangential velocity v. When the Sun disappears, the force of gravity that was keeping the Earth in circular motion disappears too: therefore, there are no more forces acting on the Earth, and so by the 1st law of Newton, the Earth will continue moving with same velocity v in a straight line.