Mindblown: a blog about philosophy.
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What is the Torque on the Object?
An object’s moment of inertia is 2.2 kg m2. Its angular velocity is increasing at the rate of 3.6 rad.sec2. What is the torque on the object? Known Variables: Angular acceleration (α)=3.6 rad/s2 Moment of inertia (I)=2.2 kg m2 Torque (τ)= α x I With this equation, τ=2.2 kg m2 x 3.6 rad/s2 τ=7.92 N*m
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Initial Angular Acceleration
The 2.3 kg object shown in the figure has a moment of inertia about the rotation axis of 8.9×10−2 kg * m2. The rotation axis is horizontal. When released, what will be the object’s initial angular acceleration? Known Variables: Mass (m): 2.3 kg Moment of inertia (I): 8.9×10-2 kg * m2 r= 17 cm or .17 m angle: 25° gravity: 9.8 m/s2…
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Moments of Inertia Ranking
Three pairs of balls are connected by very light rods as shown in the figure. Rank in order, from smallest to largest, the moments of inertia I1, I2, and I3 about axes through the centers of the rods. =I2, I1, I3
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Tangential Velocity
To throw the discus, the thrower holds it with a fully outstretched arm. Starting from rest, he begins to turn with a constant angular acceleration, releasing the discus after making one complete revolution. The diameer of the circle in which the discus moves is about 1.7m If the thrower takes 1.0s to complete one…
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Least Force Need for Application
A professor’s office door to 0.91 m wide, 2.0 m high, and 4.0 cm thick; has a mass of 25kg; and pivots on frictionless hinges. A “door closer” is attached to the door and the top of the door frame. When the door is open and at rest, the door closer exerts a torque of…
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Angular Positions of a clock
1) What is the angular position in radians of the minute hand of a clock at 5:00? To start this problem, you have to pay close attention to what they are asking: “the minute hand”. It is assumed that from 9 to 3 on the clock would make a 180 ° angle. The minute hands points at…
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What is the Angular Displacement during a Time Interval?
A child on a merry-go-round takes 3.1 s to go around once. What is his angular displacement during a 1.0 s time interval? “The period (T) is the duration of one cycle in a repeating event” Known Variables: Period: T=3.1 seconds Time: t= 1.0 second In order to find Angular displacement(Δθ), we need angular speed. First step is to find Angular speed (ω). ω=2π/T 2π/3.1=…
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What is the Angular Position?
A Ferris wheel rotates at an angular velocity of 3.9×10-2 rad/s . At t=0, your friend Seth is at the very top of the ride. What is Seth’s angular position at t= 3.4 min measured counterclockwise from the top? Give your answer as an angle in degrees between 0° and 360°. Known Variables: Angular Velocity (ω): 3.9×10-2 rad/s…
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What is the Speed?
A 5.0-m-diameter merry-go-round is initially turning with a 4.5 seconds period. What is the speed of a child on the rim? Known variables: diameter (d): 5.0 meters period (T): 4.5 seconds velocity (v)= circumference / period Circumference (c) = π x d π x 5.0= 15.707 m v=c/T v= 15.707 m /4.5 s v= 3.5m/s
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What is the Speed and Acceleration?
Your roommate is working on his bicycle and has the bike upside down. He spins the 62 cm-diameter wheel, and you notice that a pebble stuck in the tread goes by three times every second. What is the pebble’s speed? Known Variables: Angular speed: 3 rev Diameter (d) : 62 cm Convert angular speed to radians. 3…
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