Ball a (7kg) and ball b (3kg) hit each other in a perfectly elastic collision. if ball a has an initial velocity of 12 m/s and ball b has an initial velocity of -1 m/s. what are the final velocities of each ball?

Explain to someone who knows nothing about fossils the study of invertebrate paleontology and how it scientists understand the history of the earth. be sure your explanation contains a minimum of two complete sentences.

The energy released by a chemical reaction can be measured using a calorimeter. when barium hydroxide octahydrate crystals are reacted with dry ammonium chloride inside of a coffee cup calorimeter, the temperature of the 18.00 g of water in the calorimeter decreases from 30.0°c to 8.0°c. the equation for calculating energy absorbed or released by a reaction is: where q is the energy released or absorbed, m is the mass of water in the calorimeter, cp is the specific heat of water, and δt is the observed temperature change. if the specific heat of liquid water is 4.19 j/g·°c, how much energy was absorbed by the reaction?

Where do magnetic lines of force enter earth?