Search:

I haven't done this in so long even my basic math sucks.. How can I get t by itself?

sorry factor did get all messed up... it was 1*10^-4
So I can do:
1*10^-4=(1/2)^t/h ?

Half life of 15 over 8 Oxygen is 122 seconds.

How long does it take for the number of 15/8 O nuclei in a given sample to decrease by a factor of 1×10−4?
Answer in min.

I don't even know...

I knew I was off by something... thanks for your help!

Find the magnetic field 6.70 cm from a long, straight wire that carries a current of 7.80 A.
answer= B_____T

I do not know what else to do for this problem. I found this formula but it is not...

A small object is located 30.6 cm in front of a concave mirror with a radius of curvature of 40.9 cm.

So the question is Where will the image be formed?

I thought I use this equation to solve...

Sorry I am total idiot haha. Thanks for your help!

*got

OK I understand why x should be 1.6 and 1.07 but I don't understand how you go those numbers?

Given:Moe, Larry, and Curly stand in a line with a spacing of d = 1.60 m. Larry is 3.00 m in front of a pair of stereo speakers 0.800 m apart, as shown in the figure . The speakers produce a...

oh oh,I got it. I took the Area of the tip and divided by area of the crutch( circle) and got 3.1!
Pi(2.3)^2/Pi(1.3)^2
Thanks for your help!

haha maybe. So the F cancels and I have A1/A2.
Above formulas indicate that both A's are areas of crutch. Area of Crutch is Pi(1.3cm)^2. Which I get to be 5.31. So 5.31/ 5.31 is 1, but its saying...

How do I know the force applied? Gravity?

To prevent damage to floors (and to increase friction), a crutch will often have a rubber tip attached to its end.
If the end of the crutch is a circle of radius 1.3cm without the tip, and the tip...

Okay everyone Last Question I have today I promise!

Given: A 2.1-kg mass attached to a spring oscillates with an amplitude of 9.0 cm and a frequency of 4.0 Hz.
Questions:What is its energy of...

Thank you so much for help:)

Okay so 90 degrees in radians is 1.5708. I set 2(pi)(t)/ .74 equal to 1.5708.
I got t =1.8258. Is this right?

OK this one has me totally stumped. My teacher attempted to explain it in class and it made me even more confused.

Given:A child of mass m stands at rest near the rim of a stationary...

So cos=0 when theta is 90. So then I set up what's in the brackets =to 90?
Sorry I'm a little confused.

The position of a mass oscillating on a spring is given by x = ( 3.2cm)Cos[2(pi)(t)/ .74seconds]
What is the first time the mass is at the position x = 0?

I was able to calculate the period of...

That is where I messed up. I tried to multiply both side by 2 to get rid of (1/2)s.
When I set it up your way I got it right.

Thanks!

GIVEN:A 1.9 kg solid cylinder (radius = 0.20 m, length = 0.50 m) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.85 m high and 5.0 m long.

I got...

Given: A 3.0kg solid sphere (radius = 0.20m ) is released from rest at the top of a ramp and allowed to roll without slipping. The ramp is 0.75m high and 5.5m long.

Find: When the sphere reaches...

Awesome thanks for you help! :)

Okay don't think I am an idiot but I'm not getting the right answer.

I find Force=-552/3.40
I get -162.35. If R is his weight 58. I divide the force I have by 58 and I get -2.79 or -2.8. It's...

So how do I know what the normal reaction time of the batter is?

Sorry I am still a little confused. Since I have work I solved for F. F=W/d
F= .552/ 3.40? I assumed d stood for distance. Am I on...

Given:After hitting a long fly ball that goes over the right fielder's head and lands in the outfield, the batter decides to keep going past second base and try for third base. The 58 kg player...

Here you go:
http://www.flickr.com/photos/49708296@N04/5051943688/


If that doesn't work. Here is link.
http://www.flickr.com/photos/49708296@N04/5051943688/

Mechanical Advantage-
The pulley system shown in the figure is used to lift a 52- crate. Note that one chain connects the upper pulley to the ceiling and a second chain connects the lower pulley to...

Thank you so much! :)

I got:

57(2.8)^2/6 + 57(9.81)= 633

Given:Jill of the Jungle swings on a vine 6.0 m long.

What is the tension in the vine if Jill, whose mass is 57 kg, is moving at 2.8 m/s when the vine is vertical?

I believe I am going about...

Sorry I was confused for sure. I try to oversimplify too much. It's the components that always confuse me. I have a hard time visualizing it and then finding the right equations. I appreciate your...

Okay I follow you just want to make sure I'm doing this right.

My horizontal component was 17.63 and Vertical 6.766.

To solve for mg I did 32g+ 6.766 and got 38.77.

Now to find the force...

To move a large crate across a rough floor, you push on it with a force F at an angle of 21 degrees below the horizontal.

Q.Find the force necessary to start the crate moving, given that the mass...

To move a large crate across a rough floor, you push on it with a force F at an angle of 21 degrees below the horizontal.

Q.Find the force necessary to start the crate moving, given that the mass...

I set them equal to each other and got 30 degrees.
I plugged it into my online homework site and it was right!

Thank you so much!

A 45- crate is placed on an inclined ramp. When the angle the ramp makes with the horizontal is increased to 30 , the crate begins to slide downward.

Q1:What is the coefficient of static friction...