What happens to your heart rate as you increase your activity level?

What is a carrier wave and how does it affect what you hear on the radio

Where is the potential energy throughout the loading, cocking, and releasing of the trebuchet?

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. when the carts collide, they hook together. assume that positive momentum is to the right. which graph best represents the momentum of both carts over time, before and after the collision?