Physics - November 2007

A 65.0 kg ice skater moving forward with a velocity of 1.80 m/s throws a 0.280 kg snowball forward with a velocity of 26.0 m/s.

(a) What is the velocity of the ice skater after throwing the snowball? Disregard the friction between the skates and the ice.

(b) A second skater initially at rest with a mass of 60.0 kg catches the snowball. What is the velocity of the second skater after catching the snowball in a perfectly inelastic collision?

i know u use like MaVai+MbVbi = MaVaf+MbVbf for something..could someone tell me how i would use this formula for this question..? you don't have to solve it for me i just want to know how i would use this.. T_T

2007-11-04 08:45:28 · 1 answers · asked by Anonymous

' (Decay in the narrowest sense of its time/space meaning.)

2007-11-04 08:36:25 · 6 answers · asked by te144 7

What is the maximum speed with which a 1300 rubber-tired car can take this curve without sliding? (Take the static coefficient of friction of rubber on concrete to be 1.0.)

2007-11-04 07:39:38 · 4 answers · asked by venessadauby 1

a 15kg box is released on a 32 degress incline and accerlerates at 0.30 ms2 what is the friction force and the coefficent of kinetic friction

2007-11-04 07:33:17 · 3 answers · asked by Anonymous

On a horizontal frictionless table, masses A and B (3 kg, 6 kg) slide to the right and left, respectively. They have speeds of 3 m/s and 1 m/s, respectively. The two masses collide, and bounce off each other. After the collision, they travel in opposite directions at speeds of 1.5 m/s and 1.250 m/s, respectively.
(Note:In this problem, please use + dir = right, - dir = left, to indicate direction.)

a.) Calculate A's momentum:
before collision:
after collision:
Explain why it is NOT conserved.


b.) Calculate B's momentum:
before collision: kg*m/s
after collision: kg*m/s
Explain why it is NOT conserved.


c.) Calculate the A+B system's momentum:
before collision: kg*m/s
after collision: kg*m/s
Explain why IS it conserved.


d.) Calculate the kinetic energy of the A+B system:
before collision: J
after collision: J

2007-11-04 07:02:01 · 1 answers · asked by =P 6

i already know that they are
just like.. how so?
i know they use less energy, but what about their chemistry does this?
Like, i'm talking about specifics, like electrons and atoms and how all that works to make it efficient

2007-11-04 06:35:39 · 2 answers · asked by Anonymous

why is there a doppler effect when the source of sound is staionary and the listener is in motion? in which direction should the listener move to hear a higher frequency? a lower frequency?

2007-11-04 06:32:43 · 3 answers · asked by michael l 1

When looking at the physics behind the spinning of clothes in a washer, i know that the clothes are separated from the water and thus the water is not separated from the clothes. But WHY? I need a good explanation, possibly relating to centripetal acceleration or uniform circular motion. (I know that other answers were since the clothes are heavier, they are separated first, but this is not an accurate explanation as determined by my teacher). Thanks for your time.

2007-11-04 06:04:17 · 2 answers · asked by M4tr!x 2

2007-11-04 05:57:53 · 7 answers · asked by Daniela M 1

An elevator with a mass of 4850kg is to be designed so that the max acceration is 0.0680g. what are the max and min forces the motor should exert on the supporting cable

2007-11-04 05:50:44 · 1 answers · asked by Anonymous

If all matter is energy, then is it theoretically possible to convert all of someones/somethings physical matter into energy, transfer it somewhere, and reconstruct it into matter? I know this would be massive amounts of energy to deal with, but could it be done? This would be far different from cloning and destroying the original like Quantum teleportation does.

2007-11-04 05:11:54 · 4 answers · asked by Anonymous

We need to talk about the law of conversation of energy and how it applies to 3 different types of physics

um the question says

We discussed energy in many different aspects of the world. I need to use examples from class but i dont no what to do lol

we talked in class about circuits(lightbulbs,engines,generators,transformers,and some other stuff)

we talked about motion
(acceleration,velocity and what not)

we talked about friction

and some other stuff

2007-11-04 05:00:56 · 1 answers · asked by Anonymous

don't florescent lights give of ultraviolet lights? if so then why do we have the ability to visualize and and why wouldn't it be considered visible light?

2007-11-04 04:44:10 · 5 answers · asked by andy a 1

2007-11-04 03:56:51 · 3 answers · asked by Anonymous

A 13 g coin slides upward on a surface that is inclined at an angle of 12° above the horizontal. The coefficient of kinetic friction between the coin and the surface is 0.23; the coefficient of static friction is 0.31. Find the magnitude and direction of the force of friction under the following circumstances.
(a) after it comes to rest?

Whats the answer and how is it done. I cant figure out what to do.

2007-11-04 03:24:01 · 1 answers · asked by Anonymous

Consider a two slit interference pattern, for which the intensity distribution is given by

I = I(not) cos^2 (pi*d*sin(theta) / lamda)

Let θm be the angular position of the mth bright fringe, where the intensity is I(not). Assume that θm is small. Let θm+ and θm- be the two angles on either side of θm for which I=½I(not). The quantity Δθm= |θm+ -θm-| is the half-width of the mth fringe. Calculate Δθm. How does Δθm depend on m?

2007-11-04 02:48:40 · 3 answers · asked by Anonymous

Communications satellites are placed in a circular orbit where they stay directly over a fixed point on the equator as the earth rotates. These are called geosynchronous orbits. The altitude of a geosynchronous orbit is 3.58 x 10^7m. What is the period of the motion? What is the value of g at this orbit? What is the apparent weight of a 2000kg satellite at this g?




Now, I found the period to be 24hr, and the value of g to be 0.223m/s/s. But I cannot seem to find a formula to correctly calculate the apparent weight of the satellite with this information.

2007-11-04 02:18:52 · 3 answers · asked by Anonymous

An object is released from an aeroplane which is diving at angle of 30 degrees to the horizontal with a speed of 50 m/s. If the plane is at a height of 4000m from the ground when the object is released find
(a) the velocity of the object when it hits the ground
(b) the time taken by object to reach the ground
take g=9.81 m/s^2

2007-11-04 02:15:08 · 1 answers · asked by Always 4 U 2

not like a disease but just a regular itch- not from feathers and stuff either

2007-11-04 01:45:49 · 1 answers · asked by Anonymous

2007-11-04 01:37:46 · 3 answers · asked by Ahmed A 1

I've calculated the drag constant for a tennis ball (v^2 * -6.15x10^-4) and we know that vf=vi+at and df=1/2at^2+vit+di. But how would I be able to calculate the velocity and displacement at any given time, if I encompassed air resistance?
To anyone who wants to know, you can find the force of drag at any given time by: (vi+at)^2 or (-9.8t+vi)^2, where down is negative, and multiply that by the drag constant. So if you through a ball UP in the air at 30 m/s, the drag at any given time would be: f(x)=(-6.15x10^-4)*(-9.8t+30). So I want to know how to put this together in one function to find the displacement or velocity at any given point, including air resistance. Thanks!

2007-11-04 01:28:02 · 2 answers · asked by Sheen J 1

the greatest possible acceleration and deceleration that a car can have r a and 2a rsptvly,and its max speed is v.Find the minimum time in which the car can cover a dist = s.

2007-11-04 01:25:59 · 1 answers · asked by anil p 1

For these questions I have got different answers so I wanted to know which were correct.

1. The acceleration due to gravity is
A. Always directed toward the earth and therefore negative
B. Positive when velocity is positive
C. Negative when velocity is negative
D. B and C
E. None of these

(I got A and E)

18. Mac and Tosh are arguing in the cafeteria. Mac says that if he throws his jello with a greater speed it will have a greater inertia. Tosh argues that inertia does not depend upon speed, but rather upon mass. With whom do you agree and why?
A. Mac because greater speed means greater inertia.
B. Tosh because inertia depends upon acceleration.
C. Tosh because mass is a measure of inertia.
D. Mac because greater speed means greater force and force is directly proportional to inertia.
E. None of these

(I got C and A)

20. If we divide a Newton by a square meter the units that result are units of
A. Speed
B. Force
C. Mass
D. Acceleration
E. Pressure

2007-11-04 01:17:46 · 5 answers · asked by Joe T 1

A woman is reported to have fallen 144 ft from the 17th floor of a building, landing on a metal ventilator box, which she crushed to a depth of 18 inches. She suffered only minor injuries. Neglecting air resistance, calculate (a) the speed of the woman just before she collided with the ventilator, (b) her acceleration while in contact with the box, and (c) the time it took to crush the box. Then assume that the woman fell on a much “harder” surface which only crushed 2 inches, redo the calculations, and use your answers to explain why the woman was “happy” to land on the ventilator box.

2007-11-04 01:44:55 · 1 answers · asked by Anonymous

i cant solve these three problems can anyone help out?? Tnx!!!
Arigatogozaimasu!!!

What voltage is required to store 7.2 x 10-5 C of charges on the plates of a 6.0 F capacitor?

One farad is a large capacitance. To see just how large, determine the area of each plate of an empty, one farad parallel plate capacitor whose plate separation is one meter. Express your answer in square miles.

A parallel plate capacitor has a capacitance of 7.0 F when filled with a dielectric. The area of each plate is 1.5 m2 and the separation between the plates is 1.0 x 10-5 m. What is the dielectric constant of the dielectric?

2007-11-04 01:41:45 · 2 answers · asked by Anonymous

Find the magnitude and direction of the gravitational force on a fifth 2.0 kg mass placed at the midpoint of the bottom side of the square. N

Thanks for your help!

2007-11-04 01:01:20 · 3 answers · asked by cindy d 4

2007-11-04 00:14:43 · 9 answers · asked by yashvi s 2

The string is L= 80 cm long, has a ball attached to one end, and is fixed at its other end. A fixed peg is at point P. Released from rest, the ball swings down until the string catches on the peg; then the ball swings up, around the peg. if the ball is to swing completely around the peg, what value must distance d (point P) exceed? ( hint: The ball must still be moving at the top of its swing. Do yo see why?)

2007-11-04 00:08:17 · 1 answers · asked by Anonymous

2007-11-04 00:04:16 · 11 answers · asked by xenial 1

i have to write a physics investigation and I am greatly struggling, i have to write an aim, the variables.a hypotheis, method etc but its been a long time since i did the experiment so need a little help with understanding the physics behind the experiment, the title is:

to investigate how the force acting on a wire, due to a magnetic field, depends on the current flowing in the wire.

To do the experiment we made a u shaped magnet by placing the two magnadur magnets on the steel yoke with opposite poles facing each oter

we placed the magnet on the top-pan balnce to read 0

we arrange a stiff copper wire to pass centraly between the poles of the magnet

we assembled a circuit to provide a variable

i gathered some results and found the reading on the balance to go up when the current goes up ? why?? is this?? anyone got any help or advice?

2007-11-03 23:58:07 · 5 answers · asked by Anonymous