Answer:
8.91 J
Explanation:
mass, m = 8.20 kg
radius, r = 0.22 m
Moment of inertia of the shell, I = 2/3 mr^2
= 2/3 x 8.2 x 0.22 x 0.22 = 0.265 kgm^2
n = 6 revolutions
Angular displacement, θ = 6 x 2 x π = 37.68 rad
angular acceleration, α = 0.890 rad/s^2
initial angular velocity, ωo = 0 rad/s
Let the final angular velocity is ω.
Use third equation of motion
ω² = ωo² + 2αθ
ω² = 0 + 2 x 0.890 x 37.68
ω = 8.2 rad/s
Kinetic energy,
K = 0.5 x 0.265 x 8.2 x 8.2
K = 8.91 J
Answer: The velocity of the ball is 30.0 m/s
This can be calculated by using the value of acceleration as 10.0 m/s2 in free fall and the given time of 3.0 seconds. To get the
velocity, one will have to multiply the acceleration with the given time and the
quotient would result to 30.0 m/s. Mostly all object regardless of their mass,
fall to earth with the same acceleration in the absence of air resistance and as
the child drops the ball from a window, it gains speed as it falls.
Depends on how far away the event is and what the temperature is as this affects the speed of sound.
For example, let's say you're 600 meters away and the temperature has no affect.
The speed of sound would be roughly 340 m/s so the time it would take to hear the sound would be 600/340 = 1.76 seconds
The speed of light (c) is 3.0 X 10^8 m/s so the time it would take to see the event would be 600/3 X 10^8 = 2 X 10^-7
Subtract: 1.76 - (2 X 10^-7) = approx. 1.76
Answer: 1300m
Explain: from km to m times 1000
