1. Homework Statement
The isotope 239Pu has a half-life of 24,100 years. After 10,000 years, a sample of the isotope is reduced 1.6 grams. What was the intial size of the same (in grams)? How large was the sample after the first 1,000 years. Round your answer to four decimal places.
2...
1. Homework Statement
(Between 0-3) ∫x3/√(x2+9)
3. The Attempt at a Solution
I attempted U sub, but that didn't work. Neither did integration by parts; however, I do remember my teacher using a method involving sub'ing an "x" or something.
Anybody?
Will edit in attempts as I search...
1. Homework Statement
∫x3e5x2 dx
2. Homework Equations
uv-∫vdv
3. The Attempt at a Solution
I've tried this one a few times, but keep getting answers that are just out there. Could someone, if possible, work out just the beginning.
1. Homework Statement
Find the indefinite integral:
∫ Cos32x Sin22x dx
2. Homework Equations
None required
3. The Attempt at a Solution
Lost on where to start. If someone could just start me off.
1. Homework Statement
I'd like to mention beforehand this is not my work, i'm simply just trying to understand it.
I believe the answer is incorrect, could someone kindly indicate why?
A spherical navigation buoy is tethered to the sea floor by a vertical cable as
shown in the...
1. Homework Statement
Prove that the product of the kinetic energy and orbital radius of a geosynchronous satellite is constant.
2. Homework Equations
Not sure on the orbital radius part
KE=KE = ½mGM/R
3. The Attempt at a Solution
I'm lost on where to begin. How exactly would I 'prove' it?
1. Homework Statement
2. Homework Equations
The above formulas
3. The Attempt at a Solution
I'm lost on where to start with this. The object has an intial velocity in the X direction and has the resistive force of the plontons acting upon it when it lands. What exactly is...
Tricky problem worth 2 points on my final grade :)
1. Homework Statement
2. Homework Equations
I honestly don't know how to tackle this.
I think it's going to contain ƩF=mg, and some basic kinematic equations.
3. The Attempt at a Solution
Where do is start?
1. Homework Statement
I notice that when solving for k, the book often uses a positive version of the formula.
How do you know which to use?
2. Homework Equations
F=kx
F=-kx
3. The Attempt at a Solution
1. Homework Statement
http://www.youtube.com/watch?v=cM3t6Td_rYs&feature=plcp
2. Homework Equations
W=FΔrCosθ
3. The Attempt at a Solution
My questions: 1) At around 2:30, when he draws out the free body diagram, I don't understand how he comes up with these Equations. For example...
1. Homework Statement
A raindrop of mass 3.35x10-5 falls vertically at constant speed under the influence of gravity and air resistance. Model the drop as a particle. As it falls 100m, what is the work done on the raindrop. (a) by the gravitational force and (b) the air resistance.
2...
1. Homework Statement
2. Homework Equations
W=∫ Fx dx
3. The Attempt at a Solution
I think you gotta split this one in terms of axis.
∫(2yi + x2j) dx
Pretty lost on it.
1. Homework Statement
2. Homework Equations
Tan θ=A.B/|A|*|B|
3. The Attempt at a Solution
A=4i-9j
B=9i-6j
A.B=-18
Magnitude of A = √97
Magnitude of B = √117
Solve that out using Cos-1 (-18/Sqr97*Sqr117) and I keep getting the wrong answer.
1. Homework Statement
One end of a cord is fixed and a small 0.310-kg object is attached to the other end, where it swings in a section of a vertical circle of radius 2.50 m as shown in the figure below. When θ = 28.0°, the speed of the object is 9.00 m/s. At this instant, find each of the...
1. Homework Statement
A light string can support a stationary hanging load of 27.0 kg before breaking. An object of mass m = 2.81 kg attached to the string rotates on a frictionless, horizontal table in a circle of radius r = 0.809 m, and the other end of the string is held fixed as in the...
1. Homework Statement
Two blocks of masses m1 and m2, with m1 > m2, are placed in contact with each other on a frictionless, horizontal surface. A constant horizontal force is applies to m1.
a) find the magnitude of the acceleration
b) determine the magnitude of the contact force between the...
1. Homework Statement
2. Homework Equations
I believe the only necessary equations would be those utilized to find the X and Y components of a certain force as well as the formula used to find μs
µ = ffriction/fnormal
3. The Attempt at a Solution
Attempt:
I'm not really...
1. Homework Statement
2. Homework Equations
I assume, it has to do with components and forces so Fx = F Cos θ, and vice versa for the y component.
3. The Attempt at a Solution
Well, initially, I tried to add them using unit vectors and got 40.0i + 13.0j for ƩF
Solved for...
Hi guys,
I have a test in 3 hours so in trying to understand static and kinetic problems utilizing mew. Here's my problem:
A block of mass 3.00 kg is pushed up against a walk by a force P that makes the angle of theta = 30.0 angle with the horizontal. The coefficient of static friction...
1. Homework Statement
A projectile is fired from ground level with an initial velocity of 50 m/s and an initial angle of 37°. Assuming g = 9.8 m/s^2, find:
a) the projectiles total time of flight.
b) the maximum height attained
c) the total horizontal distance traveled
d) the final...
1. Homework Statement
2. Homework Equations
Above
3. The Attempt at a Solution
Okay, so I understand I need to integrate the top equation because it's velocity as a function of time.
I just don't know how.
1. Homework Statement
2. Homework Equations
x^2 + y^2 = r^2
3. The Attempt at a Solution
I understand everything, but the last segment.
What vector B when added to vector A, gives a resultant vector with no x component and a negative y component 3.34 units in length?
So 3.34 = Sqr...
1. Homework Statement
A glider of length moves through a stationary photogate on an air track. A photogate shown in the figure below is a device that measures the time interval Δtd during which the glider blocks a beam of infrared light passing across the photogate. The ratio vd = /Δtd is the...
1. Homework Statement
The height of a helicopter above the ground is given by h = 2.55t^3, where h is in meters and t is in seconds. At t = 1.65 s, the helicopter releases a small mailbag. How long after its release does the mailbag reach the ground?
2. Homework Equations
The above...
1. Homework Statement
The position of a particle moving along the x axis varies in time according to the expression x = 3t 2, where x is in meters and t is in seconds. Evaluate its position at the following times.
(
a) t = 2.30 s
(b) t = 2.30 s + Δt
(c) Evaluate the limit of...
1. Homework Statement
The radius of a solid sphere is measured to be (6.30 ± 0.26) cm, and its mass is measured to be (1.81 ± 0.08) kg. Determine the density of the sphere in kilograms per cubic meter and the uncertainty in the density. (Use the correct number of significant figures. Use the...
1. Homework Statement
A proton, which is the nucleus of a hydrogen atom, can be modeled as a sphere with a diameter of 2.4 fm and a mass of 1.67e-27 kg. Determine the density of the proton.
2. Homework Equations
As far as I know, the only required formula is D = m/v
3. The Attempt at a...