65 million years ago there was a mass extinction that is best known for killing the dinosaurs. there was also a large deposit of dust that contained substances only found in asteroids. what most likely killed off the dinosaurs?

an asteroid impact caused the sun to be blocked.
they were crushed by an asteroid.
the water supplies were polluted.
mammals evolved to be better competitors.

Suppose a force of 60 n is required to stretch and hold a spring 0.1 m from its equilibrium position. a. assuming the spring obeys hooke's law, find the spring constant k. b. how much work is required to compress the spring 0.5 m from its equilibrium position? c. how much work is required to stretch the spring 0.6 m from its equilibrium position? d. how much additional work is required to stretch the spring 0.1 m if it has already been stretched 0.1 m from its equilibrium? a. kequals 600