A 39.5 g projectile is launched by the expansion of hot gas in anarrangement shown in Figure (a). The cross-sectional area of thelaunch tube is 1.0 cm2, and the length that the projectile travelsdown the tube after starting from rest is 32 cm. As the gasexpands, the pressure varies as shown in Figure (b). The values forthe initial pressure and volume are Pi = 1.0 106 Pa and Vi = 8.0cm3 while the final values are Pf = 1.1 105 Pa and Vf = 40.0 cm3.Friction between the projectile and the launch tube isnegligible.
(a) If the projectile is launched into a vacuum, what is the speedof the projectile as it leaves the launch tube?
1 m/s
(b) If instead the projectile is launched into air at a pressure of1.1 105 Pa, what fraction of the work done by the expanding gas inthe tube is spent by the projectile pushing air out of the way asit proceeds down the tube?
A 39.5 g projectile is launched by the expansion of hot gas in anarrangement shown in Figure (a). The cross-sectional area of thelaunch tube is 1.0 cm2, and the length that the projectile travelsdown the tube after starting from rest is 32 cm. As the gasexpands, the pressure varies as shown in Figure (b). The values forthe initial pressure and volume are Pi = 1.0 106 Pa and Vi = 8.0cm3 while the final values are Pf = 1.1 105 Pa and Vf = 40.0 cm3.Friction between the projectile and the launch tube isnegligible.
(a) If the projectile is launched into a vacuum, what is the speedof the projectile as it leaves the launch tube?
1 m/s
(b) If instead the projectile is launched into air at a pressure of1.1 105 Pa, what fraction of the work done by the expanding gas inthe tube is spent by the projectile pushing air out of the way asit proceeds down the tube?
