# Search results

1. ### Murder scene

1 the problem and all known variables. A person is murdered in a room with a temperature of 20 deg C. At the time the body is discovered, the body temp is 32 deg C and is decreasing at an instantaneous rate of .1 deg C/minute. How long ago was the murder commited? 2. Related equations...
2. ### Pain measurement

I was just wondering if there's a way to measure pain. I figured it'd be and equation like current. Like voltage would be the amount of pain, ohm would be a persons resistance to pain, and current would be the pain they actually felt.
3. ### Einstein and the graviton

We know that there are force carrying particles for the strong and weak nuclear force, and the electromagnetism force. But in Einsteins theory of relativity, he states that gravity is the bending of space time, not a force. So if there is no force, why do we say there must be a graviton? Ps I'm...
4. ### Spring motion

Homework Statement When a mass is attached to a vertical spring, the spring is stretched a distance d. The mass is then pulled down from this position and released. It undergoes 57 oscillations in 39.0 s. What was the distance d? Homework Equations F=-Kx F=mg T=2pi*sqrt(K/m) The...
5. ### Two Spheres coming together

Homework Statement Two identical 28.5-kg spheres of radius 12.1 cm are 35.3 cm apart (center-to-center distance) and at rest in outer space. (You can assume that the only force acting on each mass is the gravitational force due to the other mass.) a) If they are released from rest and...
6. ### Asteroid Gravity

Homework Statement An asteroid is discovered to have a tiny moon that orbits it in a circular path at a distance of 113 km and with a period of 41.0 h. The asteroid is roughly spherical (unusual for such a small body) with a radius of 19.3 km. a) Find the acceleration of gravity at the...
7. ### Orbital Period

Homework Statement A planet with a mass of 8.99·1021 kg is in a circular orbit around a star with a mass of 1.33·1030 kg. The planet has an orbital radius of 1.21·1010 m. a) What is the linear orbital velocity of the planet? b) What is the period of the planets orbit? c) What is the...
8. ### Rocket propulsion

Homework Statement A rocket in outer space has a payload of 4050.0 kg and 1.753·105 kg of fuel. The rocket can expel propellant at a speed of 4.300 km/s. Assume that the rocket starts from rest, accelerates to its final velocity, and then begins its trip. How long will it take the rocket to...
9. ### Puck on Ice

A hockey puck on a frozen pond with an initial speed of 12.3 m/s stops after sliding a distance of 198.9 m. Calculate the average value of the coefficient of kinetic friction between the puck and the ice. So I started with finding the acceleration. I divided 12.3m/s by 198.9m then took the...
10. ### Motion of a Soccer Ball

Neglect air resistance for the following. A soccer ball is kicked from the ground into the air. When the ball is at a height of 10.07 m, its velocity is (vx,vy) = (4.63,3.83) m/s. To what maximum height will the ball rise? What horizontal distance will be traveled by the ball? With what...
11. ### Postion problem

We are given a velocity vs. time graph. It starts at 15 m/s at t=0 and goes to -10m/s at t=4 then it goes from -10m/s at t=4 to 15m/s at t=10 and we are told to find the postion after t=10 I first found the slope of the first segment which was -6.25. so I did ∫-6.25t+15 dt from 0 to 4 and...
12. ### Stuck with an acceleration problem

I know this is quite simple question. An object has an into all velocity of 50m/s it's traveling straight up. Assume g=-10m/s^2 how long does it take to go up and down? I put these numbers into x=1/2at^2+vi*t but I still have 2 variables. X and T. Idk what to do.
13. ### Intellegence of other species.

So humans have not been around the longest, obviously, but why are were we able to create civilization? Why couldn't another animal, like turtles for example, evolve to create schools, written language, tools, etc? What makes us special?
14. ### The corona sphere.

In basic, why can we only see the corona sphere during a solar eclipse? Is there a property to the eclipse or sun that causes this?
15. ### How definite integration works?

Basically my question is, how do we know that the antiderivitave of a function represents the area under that curve? If you look graphically, you can see that the area of f(x)=x from 0 to 1 is 1/2 which agrees with (x^2)/2 but why?

I accept that .999....=1, but what is the importance in that definition? What does it help us accomplish?
17. ### An apple rolling

I was walking down the street kicking and apple (why? I don't know) and I noticed that an apple, after a couple of bounces, always rolls on its side. It doesn't roll over it's stem continuosly. I was wondering why?
18. ### What is Centrifugal force?

In physics today, my teacher told me that Centrifugal force is a fake force? Is this true? What exactly is Centrifugal force? Any help would be greatly appreciated!
19. ### This girl is so confusing

This girl is so confusing!! This Is kind of a long story. So right before the school year started, me and this girl talked all the time. I really liked her and she said she liked me. After a few weeks Into the year, I asked her to be my girlfriend. And she said yes! But then she broke up...
20. ### Lorentz factor derivation

So I know about the lorentz factor and how it describes time dialition, mass increasing etc.. but I was wondering how it was derived in the first place?
21. ### Dervative of volume of sphere?

If you take the derivative of the area of a circle, you get the formula for circumference. When you take the derivative of the volume of the sphere, you do not get the formula for the area of a circle. Why not? d/dr (4/3pi r^3) =4pi r^2 d/dr (pi r^2)= 2pi r
22. ### Venn Diagram tyoe question

These kind of questions always get to me and I don't know how to solve them. Lets say that there are X many people that are in sports. Y of them are in soccer, Z of them are in cross country, and A of them are in basketball. And Y+Z+A>X How would i find out how many people do two sports or...
23. ### What is the tension in the wire?

There is a street lamp that weighs 150N. The two wires that are attached to it form at 120°. What is the tension on the wires? So i drew a diagram. Since the force of gravity acting on the lamp is 150N down, there must be an equal opposite force acting at 150N up. Then I drew a right...