# PHYS 299Int roduct ory Elect ricity, Magnet ism, and LightSpring 2015Problem Set 1Due January 21In t

PHYS 299Int roduct ory Elect ricity, Magnet ism, and LightSpring 2015Problem Set 1Due January 21In t he gure below, t hree point part icles are in place in t he xy plane. T he t hree part iles sit on t hexedcorners of an equilat eral t riangle wit h sides of lengt h a = 2:50 mm. Part icle 1 has a mass m 1 = 12:0 kg,part icle 2 has a mass m 2 = 18:0 kg, and part icle 3 has a mass m 3 = 15:0 kg.Use t he part icles described in t he gure above t o answer t he following quest ions.1. What is t he magnit ude and direct ion of t he net gravit at ional force exert ed on part icle 1 by t he ot hertwo part icles?2. What is t he magnit ude and direct ion of t he gravit at ional at point P shown on t he eldgure?3. How much work would you have t o do t o move part icle 3 t o point P ?4. Suppose you part icle 3 at it s new posit ion at point P . If you released a fourt h part icle wit h axedmass of m 4 = 40:0 kg from in ely far away, how fast would it be going when it reached t he placenitwhere part icle 3 had init ally been posit ioned?1