APPHY6.T7practicetest Try the following practice test questions. Then, compare your work to the key on the last page 1. Which of the following quantities are units of momentum? (There could be more than one correct choice.) A) N ? m B) kg ? s/m C) kg ? m/s D) N ? s E) kg ? m2/s2 2. The momentum of an isolated system is conserved A) only in inelastic collisions. B) only in elastic collisions. C) in both elastic and inelastic collisions. 3. During World War I, Germany used a "Big Bertha" cannon to hurl shells into Paris 30 miles away. This gun also had a very long barrel. What was the reason for using a long barrel in these guns? A) to exert a larger force on the shells B) to reduce frictional losses