In this animated activity, learners examine muscle cell contraction and relaxation and consider the role of calcium ions.

In this learning activity you'll solve three binary subtraction problems using the 2's complement method.

Learners follow the steps for adding and subtracting signed numbers and complete practice exercises.

In this animated and interactive object, learners view two examples of how to subtract fractions with unlike denominators and then work five similar problems.

In this learning activity you'll perform subtraction calculations using borrowing with mixed number fractions.

Learners follow step-by-step instructions for finding the lowest common denominator for a group of algebraic fractions and then enter their answers to three problems. Immediate feedback is provided. This activity has audio content.

In this interactive learning object, students calculate a resultant of multiple forces acting in a concurrent, coplanar condition.

The learner calculates the resultant of multiple forces acting in a concurrent, coplanar load condition.

In this learning activity you'll explore a step-by-step process to solve simple free-body diagrams. They identify forces acting in the x or y direction in interactive exercises.