Please, if I don't figure these out I am screwed. :wreck:and I've been trying so hard. My final is tomorrow and I'm really in a tight spot.

could anyone help me? pleeease?? you know you're out there wanting to help me:smart:

 

remember:

Kinetic Energy = 0.5mv^2

Potential Energy = 0.5kx^2

Potential Energy = mgh

W = Fdcos(angle)

 

I'll start with the first question:

 

EDIT: solved the first question. here's a few more:

 

2. solved the second

 

 

3. A 450 kg hammer mass is used as a pile diver. The hammer is raised 3.5 m above a pile. when released the hammer drives the pile 5.5 cm into the ground. What is the force delivered to the pile?

 

4. A mass is attached to a spring on a horizontal, frictionless surface. The force constant of the spring is 700 N/m. If a compression of 16 cm against the spring results in a maximum speed of 12 m/s when the mass is released, what is the value of the mass? remember, if there is no angle of applied force, W simply equals force times distance, or FD

 

5. A 45 kg student starts from rest and slides 28 m down a slide where the average force of friction is 65 N. What is the final speed of the student at the bottom of the slide if the vertical drop was 15 m?

Please, if I don't figure these out I am screwed. :wreck:and I've been trying so hard. My final is tomorrow and I'm really in a tight spot.

could anyone help me? pleeease?? you know you're out there wanting to help me:smart:

 

remember:

Kinetic Energy = 0.5mv^2

Potential Energy = 0.5kx^2

Potential Energy = mgh

W = Fdcos(angle)

 

I'll start with the first question:

 

EDIT: solved the first question. here's a few more:

 

2. There is a massless, frictionless pulley with two blocks suspended by a string. The potential energy is determined with resprect to ground level. The first block weighs 8 kg and is suspended 1.25 m above ground. The second block weighs 5 kg and is at ground level. The initial total mechanical energy in this system is:

 

A. 159 J

B. 98.1 J

C. 36.8 J

D. 0 J

 

 

3. A 450 kg hammer mass is used as a pile diver. The hammer is raised 3.5 m above a pile. when released the hammer drives the pile 5.5 cm into the ground. What is the force delivered to the pile?

 

4. A mass is attached to a spring on a horizontal, frictionless surface. The force constant of the spring is 700 N/m. If a compression of 16 cm against the spring results in a maximum speed of 2 m/s when the mass is released, what is the value of the mass? remember, if there is no angle of applied force, W simply equals force times distance, or FD

 

1 is b

thanks josh, you are oh so wise. anyone else wanna have a go at any question? any one at all...

*sigh* I think I got most of them... but I have a very very bad feeling I was wrong.

Maybe you should learn the stuff first then.

yep, wrote the test. it was all good.

and that's good advice...

Omg I thought you were really pulling your hair out :stunned: