Counterweight mass is to be M 10,000kg (10 tons),and projectile mass is m 100 kg. The length of the main beam is that of the short lever arm plus long lever arm:L 1 12 m.The Mass of the beam is 2,000 kg. This is a realistic value for an oak mass of the main beam that is 12m long.0=45 degrees. • Counterweight mass is to be M 10,000kg (10 tons), and projectile mass is m 100 kg. The length of the main beam is that of the short lever arm plus long lever arm: L + l = 12 m. The Mass of the beam is 2,000 kg. This is a realistic value for an oak mass of the main beam that is 12m long. 0=45 degrees