Question

1. IP A turntable with a moment of inertia of 5.2×10⁻³ kg⋅m2 rotates freely with an angular speed of 3313rpm . Riding on the rim of the turntable, 19 cm from the center, is a cute, 32 g mouse.

A) If the mouse walks to the center of the turntable, will the turntable rotate faster, slower, or at the same rate? (Answer is Slower)

B) Explain.

C) Calculate the angular speed of the turntable when the mouse reaches the center.

2. One elevator arrangement includes the passenger car, a counterweight, and two large pulleys, as shown in (Figure 1). Each pulley has a radius of 1.2 m and a moment of inertia of 410 kg⋅m2. The top pulley is driven by a

A) If the motor is to accelerate the elevator car upward at 1.6 m/s2, how much torque must it generate?

Express your answer to two significant figures and include appropriate units.

3. A string is wrapped around a uniform solid cylinder of radius r, as shown in (Figure 1). The cylinder can rotate freely about its axis. The loose end of the string is attached to a block. The block and cylinder each have mass m.

A) Find the magnitude α of the angular acceleration of the cylinder as the block descends.

Express your answer in terms of the cylinder's radius r and the magnitude of the acceleration due to gravity g.

4. On a part-time job, you are asked to bring a cylindrical iron rod of density 7800 kg/m3 , length 78.5 cm and diameter 2.25 cm from a storage room to a machinist. Calculate the weight of the rod, w. The acceleration due to gravity, g = 9.81 m/s2 .

Answer 1

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