# Physics circular motion and gravity help please

1. Jun 8, 2013

### katiegerster

physics circular motion and gravity help please :(

1. a) A solid homogeneous sphere of mass M = 4.80 kg is released from rest at the top of an incline of height H=1.35 m and rolls without slipping to the bottom. The ramp is at an angle of θ = 25.7o to the horizontal. Calculate the speed of the sphere's CM at the bottom of the incline.

b) Determine the rotational kinetic energy of the sphere at the bottom of the incline.

2. A mass M=169 kg is suspended from the end of a uniform boom.The boom (mass=90.0 kg, length=3.60 m) is at an angle θ=68.0 deg from the vertical, and is supported at its mid-point by a horizontal cable and by a pivot at its base. Calculate the tension in the horizontal cable.

3. A plank of length L=1.800 m and mass M=7.00 kg is suspended horizontally by a thin cable at one end and to a pivot on a wall at the other end.The cable is attached at a height H=1.50 m above the pivot and the plank's CM is located a distance d=0.700 m from the pivot. Calculate the tension in the cable.

2. Jun 8, 2013

### darkxponent

First show us the attempt.

3. Jun 8, 2013

### katiegerster

i actually just figured out question one
but i dont even know how to start 2 and 3 :(

4. Jun 8, 2013

### darkxponent

To start the second one. First draw the Diagram. Then draw the FBD. Show it to us. Same applies for the third one.

Drawing the physical diagram would give you a rough idea of the system.

hint: Both systems are in equlibirium.

5. Jun 8, 2013

### darkxponent

And one more thing. You must show us your attempt to get any further help. If you cant show the attempt, you have to tell us your progress.