# Search results

1. ### 1-D Kinematics Problem

Even if it's quadratic, why wouldn't you be able to solve for t?
2. ### 1-D Kinematics Problem

Why can't you solve for t?
3. ### Free-fall gravity problem

Yes, when the object is in freefall on Earth, gravity = a = 9.8m/s^2 down. Signs are optional but you could say -9.8n/s^s. In 2D, the gravity is always 9.8m/s^2 down on the object. It doesn't matter how the object is moving or thrown, gravity is always down.
4. ### Acceleration due to Gravity

Hitchhikers reference eh? The other object should be the falling whale.
5. ### Kinematics Problem

I just gave you the answer.

Oh I see. Thanks for setting me straight. I'm still learning and your opinion is very helpful to me.

Area of wire, cross section area.

Well, circumference=pi*diameter, lol 102 turns = 102 circumferences

Oh I see. What's the step after finding R?
10. ### Kinematic graphs

The graph of the acceleration is the graph of the derivative of the v-graph. Find the slope at each second and graph it onto a new graph. The a-graph is not linear.

Isn't the L for B=UIN/L the length of the solenoid not the length of the wire?
12. ### Conservation of Energy max height

Break the velocity into components.

Yes, i know.
14. ### Kinematics Problem

Wait, I think it was the d for the 4th second, from 3-4s. Because the first second is 0-1s, second second is for 1-2s, etc. So Vf=vo+at V@3=5+9.8*3 and V@4=5+9.8*4 Vf^2=Vo^2+2ad (V@4)^2=(V@3)^2+2*9.8*d Find d
15. ### Kinematics Problem

Well, d=Vot+.5at^2 so d should be 98.4m. Did you get that?

How do you know its wrong?
17. ### Determine distance traveled up an incline w/ friction

Mass is mass. There is no component of mass, just component of weight.
18. ### Determine distance traveled up an incline w/ friction

Come again?

B=µoNI/2r, B is magnetic force, µo is magnetic constant, N is number of turns, I is current, r is radius I think that's it but that R is unused in the problem, and it concerns me that I missed something.
20. ### Determine distance traveled up an incline w/ friction

Yes. There is friction force and it cause it to decelerate. Ff=ma, try that.
21. ### Determine distance traveled up an incline w/ friction

Did you draw a force diagram? Ff=uFn, Fn is a component of weight. Is there an answer to compare to?
22. ### Conservation of Energy max height

Max height has to do with potential energy. Kinetic energy at max height is a conceptual question and idea.

Is there an answer to compare to at the back of the book?
24. ### Bullet passing through 4cm thick board

Did I get it right?

26. ### Liquids and densities help please! due tommorow

Well, you are right up to the last part of 21.398N. You also need to account for the Fb of the lead underwater.
27. ### EMF and circuits

Is there an answer in the back of the book to compare to?
28. ### Liquids and densities help please! due tommorow

Isn't that volume of cylinder?
29. ### Series Problem. Help?

V=IR Both: 12=(R1+R2)I; R2 removed: 12=R1(I+.2) R1 removed: 12=R2(I+.1) Solve for R's R1=12/(I+.2) R2=12/(I+.1) Plug into original equation 12=(12/(I+.2)+12/(I+.1))I Solve for I I=.1414 Plug I back into R1 and R2 R1=12/(.1414+.2)=35.15ohm R2=12/(.1414+.1)=49.7ohm
30. ### Bullet passing through 4cm thick board

First off, deceleration is constant, if the board is uniform. The equation you use is d=.5(vo+vf)t. d, vo, vf is given. Also, don't forget to convert cm to m.