Final answer:
To find the tension in the string as a 4 kg ball rotates around a 7-meter radius circle, we need the ball's velocity, which is not provided. Without velocity, we cannot compute the tension accurately using the required formula.
Step-by-step explanation:
To calculate the tension in the string when a 4 kg ball is rotating in a circle of radius 7 meters, we must understand the concept of circular motion. The tension in the string provides the necessary centripetal force to keep the ball in circular motion. However, the question does not provide the angular or linear speed of the ball. Without this, we cannot determine the tension in the string because the tension depends on the velocity of the ball as well as its mass and the radius of the circle.
In formulas, the tension T would be calculate using by the equation T = m*v^2 / r, where m is the mass of the object, v is the linear speed, and r is the radius of the circular path. Since the linear speed v is not given, it is not possible to provide a correct numerical answer to the question. Therefore, additional information is needed to solve this problem.