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Grade 11Electric Current

A cylinder rapidly spinning about horizontal axis was dropped from height h=5 meterand landed at distance d = 0.5 meter from the the point directly below its initial position.Cylinder:mass m = 10 kglength L = 1 meterradius r = 10 cmEnvironment:acceleration of gravity g = 10 m/s²density of air ? = 1kg/m³How fast was the cylinder spinning?

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12 Years agoGrade 11
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1 Answer

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ApprovedApproved Tutor Answer0 Years ago

To determine how fast the cylinder was spinning when it was dropped, we can analyze the motion of the cylinder as it falls and travels horizontally. The key here is to understand the relationship between the vertical drop, the horizontal distance traveled, and the angular velocity of the cylinder.

Breaking Down the Problem

We know the following parameters:

  • Height of the drop (h) = 5 meters
  • Horizontal distance (d) = 0.5 meters
  • Mass of the cylinder (m) = 10 kg
  • Length of the cylinder (L) = 1 meter
  • Radius of the cylinder (r) = 0.1 meters
  • Acceleration due to gravity (g) = 10 m/s²

Calculating the Time of Fall

First, we need to find out how long it takes for the cylinder to fall from a height of 5 meters. We can use the formula for the time of free fall:

t = √(2h/g)

Substituting the values:

t = √(2 * 5 m / 10 m/s²) = √(1) = 1 second

Horizontal Motion Analysis

Next, we analyze the horizontal motion. The horizontal distance traveled by the cylinder is given as 0.5 meters. Since we know the time of fall is 1 second, we can find the horizontal velocity (v) of the cylinder:

v = d/t

Substituting the values:

v = 0.5 m / 1 s = 0.5 m/s

Relating Linear Velocity to Angular Velocity

The linear velocity of the edge of the spinning cylinder is related to its angular velocity (ω) by the formula:

v = ω * r

Where r is the radius of the cylinder. Rearranging this gives us:

ω = v / r

Now substituting the values we have:

ω = 0.5 m/s / 0.1 m = 5 rad/s

Final Thoughts

The angular velocity of the cylinder when it was dropped is therefore 5 radians per second. This means that as the cylinder fell, it was spinning rapidly enough to cover the horizontal distance of 0.5 meters in the time it took to fall 5 meters. Understanding this relationship between linear and angular motion is crucial in physics, especially in problems involving rotational dynamics.