the element born has two stable isotopes. boron-10 has an atomic mass of 10.0129 and a percentage in nature of 19.78% the atomic mass of boron-11 is 11.0093 and its percentage in nature is 80.22% what is the average atomic mass for boron?

60 2(x + 2) in the diagram, gef and hef are congruent. what is the value of x?

Aremote-controlled boat can travel at 4 feet per second in calm water. the boat traveled 48 feet with the current, and then it traveled 16 feet against the current in the same amount of time. how fast is the current?

Amass weighing 16 pounds stretches a spring 8/3 feet. the mass is initially released from rest from a point 2 feet below the equilibrium position, and the subsequent motion takes place in a medium that offers a damping force that is numerically equal to 1/2 the instantaneous velocity. find the equation of motion if the mass is driven by an external force equal to f(t)=cos(2t).