Turntable rotation homework

For question 2, the solid ball. The mass is 1.6 kg and the diameter is 20 cm, so the radius is 10 cm or 0.1 m. The angular velocity is 64 revs per minute, which is ω0 = 6.707 s-1. The moment of inertia is given by I = 2/5 * m * r^2 = 2/5 * 1.6 * 0.1^2 = 0.00512 kg m^2. Using the formula for kinetic energy, we get KE = 1/2 * I * ω0^2 = 1/2 * 0.005
  • #1
Gtseviper
Please help

When a turntable rotating at 32 1/3 rev/min is shut off, it comes to rest in 29 s.

a assuming constant angular accelerationn, find the angular acceleration.
(my work) W-Wo/t=a and I got -.12

b number of revolutions
(my work) phida-initial phida= Wot + 1/2at^2 and I got 8.03 rev

2 A solid ball of mass 1.6kg and diameter 20 cm is rotating about its diameter at 64rev/min

a What is its KE.
(my work) K= 1/2 Iw^2, I=2/5 MR^2 I= 2.56 x10^-2 kg m^2 K= 5.75 x 10^-1 J

b addition 2 J is added, new angular speed.
(my work) 2.57 J is new K, W^2= 2K/I W= 1.36 x 10^2 rev/min

3 A 1300-kg car is being unloaded by a winch. At the moment shown in Figure 9-46, the gearbox shaft of the winch breaks, and the car falls from rest. During the car's fall, there is no slipping between the (massless) rope, the pulley, and the winch drum. The moment of inertia of the winch drum is 300 kg · m2 and that of the pulley is 2 kg · m2. The radius of the winch drum is 0.80 m and that of the pulley is 0.30 m. Find the speed of the car as it hits the water.

and I got 8.89 by using mgh= 1/2 Iw (V/rw)^2+ 1/2 Ip (V/rp)^2 mv^2
 

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  • #2
For question 1, the turntable. 32 1/3 revs per minute gives ω0 = 0.5389 s-1.
The angular acceleration (assuming constant) gives α = (0-ω0)/t = - 0.5389 / 29 = 0.018582 s.
Can you find the correct number of revolutions now? Keep in mind that one revolution is 2π
 

1. How do I determine the direction of turntable rotation for my homework?

To determine the direction of turntable rotation, you can use the right-hand rule. Place your right hand on the turntable with your fingers pointing in the direction of rotation. Your thumb will then point in the direction of the rotation.

2. What is the purpose of turntable rotation in my homework?

Turntable rotation is used in experiments and calculations to simulate the rotation of Earth or other celestial bodies. This allows for the study of various phenomena, such as gravity and motion, in a controlled environment.

3. How do I calculate the speed of turntable rotation for my homework?

The speed of turntable rotation can be calculated by dividing the angle of rotation in radians by the time it takes for one complete rotation. This will give you the angular velocity in radians per second. You can then convert this to revolutions per minute (RPM) by multiplying by 60.

4. What are some common applications for turntable rotation in scientific research?

Turntable rotation has various applications in scientific research, including studying centripetal and centrifugal forces, simulating the rotation of planets and galaxies, and testing the effects of rotation on biological systems.

5. Do I need any special equipment to perform turntable rotation for my homework?

Yes, you will need a turntable or rotating platform to perform turntable rotation for your homework. Additionally, you may need other equipment such as a motor or pulley system to control the speed and direction of rotation.

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