A roller coaster car, which rapidly picks up speed as it rolls down a slope. As it starts down the
slope, its speed is 4 m/s. But 3 seconds later the speed
is 25 m/s. What is its average acceleration?

How will each of the following changes in demand and/or supply affect equilibrium price and equilibrium quantity in a competitive market; that is, do price and quantity increase or decrease, or are the answers indeterminate because they depend on the magnitudes of the shifts?

Which one of the following research methods can show cause and effect

Suppose a wire with a current is pushed upward by a magnetic field. how would the wire move if the direction of the current reversed? explain your answer.