Calculating Revolutions in 1.0 s with Given Tension and Moment of Inertia

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In summary, a fisherman with a rod and reel experiences a tension force of 65 N when a large fish strikes the bait. For a reel with a moment of inertia of 4.0 * 10^-3 kg-m2 and a radial distance of 4.0 cm, the number of revolutions of the reel in 1.0 second is 52, assuming negligible friction. The angular acceleration is 650 rad/sec, and the angular velocity is 103 rev/sec.
  • #1
Miike012
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Problem:
A large fish strikes bait cast by a fisherman with a rod
and reel. The fish creates tension in the line of 65 N.
How many revolutions of the reel occur in 1.0 s if the
reel has a moment of inertia of 4.0 * 10^-3 kg-m2 and the
radial distance of the line from the reel’s axis is 4.0
cm? Assume the reel has negligible friction.


Solution:

calculated Torque from tension force: 65N*.04m = 2.6

ƩTorque = I*(angular Acceleration)
2.6/ ( 4.0 10^-3) = angular Acceleration = 650

(650)*(1sec) = Angular Velocity = 650 rad/sec * rev/(2pi) = 103 rev/sec.

What am I doing wrong? the answer is 52 rev
 
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  • #2
Sorry... I just realized what I did wrong... I solved for ang velocity instead of theta...
 

1. How do you determine the revolution of an object?

Determining the revolution of an object involves measuring the time it takes for the object to complete one full rotation around its axis. This can be done using a stopwatch or by counting the number of rotations in a given time period.

2. What units are used to measure revolutions?

The most commonly used unit for measuring revolutions is the revolution per minute (RPM). However, revolutions can also be measured in radians per second (rad/s) or degrees per second (°/s).

3. How is the revolution of a planet calculated?

The revolution of a planet is calculated using Kepler's Third Law of Planetary Motion, which states that the square of a planet's orbital period is proportional to the cube of its average distance from the Sun. This can be represented by the equation T^2 = (4π^2/GM)r^3, where T is the orbital period, G is the gravitational constant, M is the mass of the central body (in this case, the Sun), and r is the average distance between the planet and the Sun.

4. Can the revolution of an object change?

Yes, the revolution of an object can change. Factors such as gravitational pull, changes in velocity, and external forces can affect the revolution of an object. For example, a planet's revolution can change due to the gravitational pull of other celestial bodies or if it experiences a change in its own velocity.

5. Why is determining revolutions important in science?

Determining revolutions is important in science because it helps us understand the motion and behavior of objects in space and on Earth. It also allows us to make predictions and calculations for various scientific and technological applications, such as predicting the position of planets, designing machinery, and understanding the effects of rotation on weather patterns.

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