Physics Homework Help?

Question

A 4.00-kg mass and a 3.00-kg mass are attached to opposite ends of a very light 42.0-cm-long horizontal rod (the figure). The system is rotating at angular speed ω = 5.55 rad/s about a vertical axle at the center of the rod.(Figure 1)

Part A

Determine the kinetic energy KE of the system.

 

Part B

Determine the net force on 4.00 kg mass.

Part C

Determine the net force on 3.00 kg mass.

 

Answer 1

(a)

Step1:

The masses are and .

The two masses are attached to a long horizontal rod of length is .

The angular speed of the system is .

The kinetic energy is , where is the moment of inertia.

The moment of inertial of the system is .

.

Substitute , and .

kg-m².

Step 2:

Find the kinetic energy of the system.

Substitute , in .

= 4.75 J.

The kinetic energy of the system is 4.75 J.

Solution:

The kinetic energy of the system is 4.75 J.

Answer 2

(b)

The masses are and .

The two masses are attached to a long horizontal rod of length is .

The angular speed of the system is .

Find the net force on mass.

The net force on mass is .

Substitute , and .

.

The net force on mass is .

Answer 3

(c)

The masses are and .

The two masses are attached to a long horizontal rod of length is .

The angular speed of the system is .

Find the net force on mass.

The net force on mass is .

Substitute , and .

.

The net force on mass is .