How many neutrons make up one of these potassium atoms?

19
20
38
58

Which of the following are appropriate acceleration units?

Two masses are connected by a rope that hangs over a pulley as shown below. the pulley is a uniform cylinder of radius 푅=0.381meters and mass 푀=3.1푘푔. initially 푚"is on the ground and 푚#rests 2.5 meters above the ground. if the system is released, use conservation of energy to determine the speed of 푚#just before it strikes the ground. assume the pulley bearing is frictionless.

Calculate a pendulums frequency of oscillation (in hz) if the pendulum completes one cycle in 0.5s.