When a person bends an arm a different muscle is used to bring it back to the original position. why can't the same muscle be used to both bend and unbend the arm?

Two polarizers are oriented at 24.0∘ to one another. light polarized at a 12.0-degree angle to each polarizer passes through both. what is the transmitted intensity (%)?

Immediately upon reaching its lowest point, a falling pendulum bob has its greatest amount of energy, which is the initial amount of potential energy. a. heat; less than b. heat; more than c. kinetic; less than d. kinetic; more than

This punnett square shows the cross between two pants. one parent has round seeds (rr). and the other parent has wrinkled seeds (rr) which best describes their offspring as shown in this cross?