1. The problem statement, all variables and given/known data A string is attached to a 10 kg block that lies on a horizontal surface. If the string is pulled horizontally with a force of 50 N, friction acting against it is 30 N. What is the tension in the string? 2. Relevant equations F = ma 3. The attempt at a solution Would it be 50 N? Friction wouldn't matter. Or does it matter? The answer is 80 N?