A spherical mirror used in solar furnace focuses sunlight on its principal axis at a distance 12 cm from its pole. The radius of curvature of the mirror is 20 POINTS

Natural forces that can alter ecosystems include seasons and climate changes. t or f

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Determine the force the sun exerts on an object with a mass of 80.0 kg if that object is on the earth. what is the force exerted by the moon on the same object? what is the force the earth exerts on it?