Category: General Physics
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Angular Acceleration and Revolutions
The crankshaft in a race car goes from rest to 3500 rpm in 3.5 seconds. What is the crankshaft’s angular acceleration? Known Variables: time: 3.5 seconds angular frequency(ω): 3500 rpm We know that the angular acceleration formula is as follows: α= ω/t First we need to convert ω into proper units which is in radians/second. 3500 rpm…
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What Force Must You Pull
The tune-up specifications of a car call for the spark plugs to be tightened to a torque of 35 Nm. You plan to tighten the plugs by pulling on the end of a 21-cm-long wrench.Because of the cramped space under the hood, you’ll need to pull at an angle of 125° with respect to the wrench shaft. With what force must…
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What is the Torque?
Tom and Jerry both push on the 3.10 m-diameter merry-go-round shown in the figure. If Tom pushes with a force of 39.3 and Jerry pushes with a force of 35.5 , what is the net torque on the merry-go-round? Known variables: diameter: 3.10 m or radius: 1.55 m Force_1= 39.3 N Force_2: 35.5 N Force_1 angle: 60° Force_2 angle: 80° First off, we…
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What is the Magnitude of the Torque?
An athlete at the gym holds a 4.0 kg steel ball in his hand. His arm is 70 cm long and has a mass of 4.0 kg. 1) What is the magnitude of the torque about his shoulder if he holds his arm straight out to his side, parallel to the floor? Known Variables: Mass of Arm: 4 kg…
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Distance from the Center of Gravity of a Object
Two thin beams are joined end-to-end as shown in the figure to make a single object. (The object is seen from the side.) The left beam is 11.3 kg and 1.00 m long and the right one is 41.0 kg and 2.00 m long. How far from the left end of the left beam is the center of gravity of the…
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Moment of Inertia
A regulation table tennis ball has a mass of 2.5 g and is 42 mm in diameter. What is its moment of inertia about an axis that passes through its center? Known Variables: m: 2.5 g or .0025 kg d: 42 mm or .042 m r= .042/2 = .021m Moment of Inertia for a hollow sphere I =(2/3) x m x r²…
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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…