Which statements show the importance of clean air? Check all that apply. Air is a natural resource. Governments manage air pollution to provide clean air. Lungs naturally purify the air, so air pollution does not harm people. Ultrafine particles contribute to 17,000 deaths per year in the United States. Particles in the air cause health problems.

An electron and a proton have the same kinetic energy upon entering a region of constant magnetic field and their velocity vectors are perpendicular to the magnetic field. suppose the magnetic field is strong enough to allow the particles to circle in the field. note: you'll need to look up the masses for an electron and proton. 1) what is the ratio of the radii of their circular paths rp/re?

The 10-kg double wheel with radius of gyration of 125mm about o is connected to the spring of stiffness k = 600 n/m by a cord which is wrapped securely around the inner hub. if the wheel is released from rest on the incline with the spring stretched 225 mm, calculate the maximum velocity v of its center o during the ensuing motion. the wheel rolls without slipping

What is the mass of the same rock on the earth