True because well it’s moving fast lol sometimes ur eyes have a hard time following its speed
Answer:
a. 16 s b. -1.866 kJ
Explanation:
a. Since the initial rotational speed ω₀= 3313 rev/min = 3313/60 × 2π rad/s = 346.94 rad/s. Its rotational speed becomes ω₁ = 0.75ω₀ in time t = 4 s.
We find it rotational acceleration using α = (ω₁ - ω₀)/t = (0.75ω₀ - ω₀)/t = ω₀(0.75 - 1)/t = -0.25ω₀/t = (-0.25 × 346.94 rad/s)/4 s = -21.68 rad/s².
Since the turntable stops at ω = 0, the time it takes to stop is gotten from
ω = ω₀ + αt and t = (ω - ω₀)/α = (0 - 346.94 rad/s)/-21.68 rad/s² = (-346.94/-21.68) s = 16 s.
So it takes the turntable 16 s to stop.
b. The workdone by the turntable to stop W equals its rotational kinetic energy change.
So, W = 1/2Iω² - 1/2Iω₀² = 1/2 × 0.031 kgm² × 0² - 1/2 × 0.031 kgm² × (346.94 rad/s)² = 0 - 1865.7 J = -1865.7 J = -1.8657 kJ ≅ -1.866 kJ
Answer:
The density of the mixture is 0.55kg/m^3
Explanation:
P = 1bar = 100kN/m^2, T = 0°C = 273K, n = 0.4+0.6 = 1mole
PV = nRT
V = nRT/P = 1×8.314×273/100 = 22.70m^3
Mass of N2 = 0.4×28 = 11.2kg
Mass of H2 = 0.6×2 = 1.2kg
Mass of mixture = 11.2 + 1.2 = 12.4kg
Density of mixture = mass/volume = 12.4/22.7 = 0.55kg/m^3
Answer:
7 miles northeast is the because it has both magnitude and direction .