A cannon of mass 1500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 30° above the horizontal. Find the recoil velocity of the cannon across the level ground
a. 1.15 m/s
c. 2.41 m/s
b. 0.94 m/s
d. 1.94 m/s
A
You might also like to view...
A 2.5-cm-thick sheet of plastic initially at 21°C is placed between two heated steel plates that are maintained at 138°C. The plastic is to be heated just long enough for its midplane temperature to reach 132°C. If the thermal conductivity of the plastic is 1.1 × 10–3 W/(m K), the thermal diffusivity is 2.7 × 10–6 m2/s, and the thermal resistance at the interface between the plates and the plastic is negligible, calculate: (a) the required heating time, (b the temperature at a plane 0.6 cm from the steel plate at the moment the heating is discontinued, and (c) the time required for the plastic to reach a temperature of 132°C 0.6 cm from the steel plate.
GIVEN
• A sheet of plastic is placed between two heated steel plates
• Sheet thickness (2L) = 2.5 cm = 0.025 m
• Initial temperature (To) = 21°C
• Temperature of steel plates (Ts) = 138°C
• Heat until mid-plane temperature of sheet (Tc) = 132°C
• The thermal conductivity of the plastic (k) = 1.1 × 10–3 W/(m K)
• The thermal diffusivity (?) = 2.7 × 10–6 m2/s
• The thermal resistance at the interface between the plates and the plastic is negligible
FIND
(a) The required heating time (b) The temperature at a plane 0.6 cm from the steel plate at the moment the heating is discontinued (c) The time required for the plastic to reach a temperature of 132°C 0.6 cm from the steel.
ASSUMPTIONS
• The initial temperature of the sheet is uniform
• The temperature of the steel plates is constant
• The thermal conductivity of the sheet is constant
SKETCH
How many moons does earth have
A) none B) one C) two D) three E) four
The number of protons in the nucleus of an atom determines
A. the half-life of the nucleus. B. the atomic mass. C. the density of the nucleus. D. the number of neutrons in the nucleus.
The half-life of 18N is 0.62 s. What is the decay constant for this isotope?
a. 0.43 s–1 b. 1.1 s–1 c. 1.7 × 10^–11 Ci d. The decay constant is not defined for a half-life of less than one second.