Physics - March 2007

a skateboarder slides down a frictionless ramp inclined at an angle 30degrees to the horizontal.he then slides across a frictionless horizontal floor and begins to slide up a second incline at an angle of 25degrees to the horizontal.the skateboarder starts at a distance of 10m from the bottom of the first incline.how far up the second incline will he go if the coefficient of kinetic friction on the second incline is 0.10?

the answer is 9.8 metres

thanks!!!!

2007-03-06 04:34:23 · 1 answers · asked by Anonymous

2007-03-06 04:18:49 · 5 answers · asked by jayashree d 2

A small immersion heater is rated at 352 W. Estimate how long it will take to heat a cup of soup (assume this is 250 mL of water) from 20°C to 50°C

HELP!!!

2007-03-06 04:16:24 · 1 answers · asked by m s 1

After a coin was accidently dropped on the floor, it is rolling around the circle R = 0.4m. The speed of the coin v = 1.00 m/s. What is the inclination angle of the coin to the vertical?

The coin is a thin uniform disk of radius r << R.
The force of friction is sufficient to keep the coin from slipping.
Ignore all enrgy losses, air, etc..

2007-03-06 04:15:53 · 3 answers · asked by Alexander 6

Standard ping pong is 2.7 gram, 40 mm diameter ball.
Estimate initial acceleration of the ball if it is submerged
in mercury and then released.

Note the word 'estimate'.

2007-03-06 04:10:57 · 2 answers · asked by Alexander 6

a young tree branch bends in the wind. an old tree branch breaks off under the same conditions. discuss the differences in the physical properties of the two branches.

2007-03-06 04:05:54 · 3 answers · asked by Anonymous

My physics teacher gave us a theoretical type of problem involving 3-dimensionl forces, though we've only studied 2-dimensional. I'm not exactly sure how they work, so can someone give me a little advise? The problem is:

You have 3 non net-zero forces acting on a particle located at the origin. F1 is in the positive z-plane. How can you make F2 and F3 (which are in and must stay in the x- & y-planes) so that the particle experiences no acceleration?

I'm assuming the particle will move, but we want to counteract the z-plane force with a net force so that the particle moves at constant velocity. Not sure how to do that though. Any ideas? Thanks.

2007-03-06 03:58:42 · 4 answers · asked by William W 1

A uniform electric field is directed upward and has a magnitude of 6 N/C. What are the magnitude and direction of the force on a charge of -9 C placed in this field?
N

upward
or
downward

2007-03-06 03:51:10 · 1 answers · asked by TROD 1

the density of silver is 10.5g/cm cubed.

do not use an algebraic equation.

2007-03-06 03:36:53 · 1 answers · asked by Anonymous

2007-03-06 03:09:21 · 2 answers · asked by martinmm 7

2007-03-06 03:08:08 · 5 answers · asked by Anonymous

2007-03-06 02:38:15 · 8 answers · asked by alex d 1

There are 4 dimesions that we can experience and measure, although we can only travel in one direction through time, I wonder what the other dimensions are like.

2007-03-06 02:38:05 · 5 answers · asked by misoma5 7

being more specific:What type of transversal waves do tv's emit?

2007-03-06 02:36:40 · 1 answers · asked by Anonymous

what scientific ways are there of measuring distance e.g. ultrasound. no stupid answers like use a ruler please

2007-03-06 02:36:16 · 7 answers · asked by pearls3212 4

I have no idea how to solve the second part of this problem (Part B). Can anyone point me in the right direction?

A slide projector has a converging lens whose focal length is 104.50 mm.

(a) How far (in meters) from the lens must the screen be located if a slide is placed 108.80 mm from the lens?
Answer is 2.64409 m

(b) If the slide measures 24.0 mm x 36.0 mm, what are the dimensions (in mm) of its image?
_____ mm x ______ mm

2007-03-06 02:33:51 · 2 answers · asked by larkinfan11 3

At t=0 the current to a dc electric motor is reversed, resulting in an angular displacement of the motor shaft given by theta(t) = (A)t - (B)t^2 - (C)t^3.

(a) How many revolutions does the motor shaft turn through between the time when the current is reversed and the instant when the angular velocity is zero?

(b) Calculate the average angular velocity for the time period from t=0 to the time when the angular velocity of the motor shaft zero.

Thanks for the help, sorry it's such a long problem!

2007-03-06 02:33:05 · 3 answers · asked by Amanda 2

A small ball of mass m is aligned above a larger ball of mass M = 0.77 kg (with a slight separation, as with the baseball and basketball), and the two are dropped simultaneously from height h = 2.1 m. (Assume the radius of each ball is negligible relative to h.)



(a) If the larger ball rebounds elastically from the floor and then the small ball rebounds elastically from the larger ball, what value of m results in the larger ball stopping when it collides with the small ball?
kg
(b) What is the maximum height the small ball then reaches?
m

2007-03-06 02:18:22 · 2 answers · asked by x2carlosp 2

A steel ball of mass 0.600 kg is fastened to a cord that is 60.0 cm long and fixed at the far end. The ball is then released when the cord is horizontal . At the bottom of its path, the ball strikes a 3.00 kg steel block initially at rest on a frictionless surface. The collision is elastic.


(a) Find the speed of the ball just after collision.
m/s
(b) Find the speed of the block just after collision.
m/s

2007-03-06 02:16:44 · 3 answers · asked by x2carlosp 2

folks,
what is meant by load in electronic circuits. what does they do.
please explain

2007-03-06 02:14:53 · 3 answers · asked by aparna 1

You check conservation of the total mechanical energy by comparing the change in potential energy of the mass m with the change in kinetic energy, delta dKE, of the masses m and M combined, which is 340grams . The change in kinetic energy is dKE = 1/2(m+M)v2 (see Ch6 sheet 8), where v is the velocity of the glider when starting with zero initial velocity, v = 0.5 m/s. In your error calculations you have previously determined the error of the term [ 1/2(m+M) ] to be 1.138%, and the relative error of the velocity v to be 0.00855. What is the absolute error of dKE ?

the answer is .000873 but i need to understand how to get it, please help

2007-03-06 02:09:59 · 1 answers · asked by Paul S 2

2007-03-06 01:59:32 · 2 answers · asked by christian_cag 1

*what vibrates to make the wave
*how big are the waves
* wave length
*what will stop the waves
*why are they radioactive and what does that mean (radioactive)

2007-03-06 01:52:12 · 3 answers · asked by alex d 1

folks,
what is the role of resistance in circuits? for example in logic gates, fet, clipper we use resistance, if resistance is meant for resisting the current how do we get output. my question may sound foolish, but please make me understand the role of resistance in electronic circuits.
one more thing in logic gates also we use resistance but we get the output. how is it possible if resistance obstructs current

2007-03-06 01:49:22 · 3 answers · asked by aparna 1

folks,
in lorentz force we have f=b(q*V) which reduces to bqvsinTheta.
sin is understandable because this is a cross product.
but in deriving tangent law in magnetism we get cos Theta while using cross product? how

2007-03-06 01:42:35 · 1 answers · asked by aparna 1

what is torque?...i know its not a force...but still in some wierd way it looks like force.....what is it?...the force that turns a body??.....if so can it still be measured in newtons...if yes y is it not force???and what really is moment?...the analog to mass in non rotating world???

2007-03-06 01:38:23 · 5 answers · asked by lilmissy 2

1. Water flows through a 2 cm opening in the side of a tank. If the opening is 8 m below the surface of the water,what volume of a water would escape from the tank per minute?If a stream of water escapes from another hole 2 m above the base of the tank and strikes the ground at a horizontal distance of 25 m.How far below the surface of the water is the hole?

2. A sphere 1 m in diameter floats half submerged in a tank of oil( Sg = 0.80). a.) What is the upward force acting on the sphere? b.) What is the minimum weight of an anchor w/ a density of 20,000 N/m^3 that will be required to submerge the sphere completely? c.) What minimum weight of a body placed on the top of the sphere will be required to just submerge sphere completely?

thanks for the help

2007-03-06 01:23:42 · 1 answers · asked by jhen_hidaka 1

I attend to polish high school. During all classes we have light switch on. It is so annoying. Even when the sun is shinig. Isn;t it a waste of energy?
What do you think? SOme ppl say that it damages our eyes. Is it true?

2007-03-06 01:03:08 · 3 answers · asked by aneta0412 2

A rock is thrown straight upward from the edge of a 30 meter cliff, rising 10 meters then falling all the way down to the base of the cliff, find the rocks displacement.

2007-03-06 01:01:40 · 2 answers · asked by Anonymous

Rita is waiting at a cafe for her taxi. She has ordered a turkish coffee and needs to drink it quickly. However the coffee is too hot. Should she add a little cold water and allow the coffee to cool or should she wait for the coffee to cool and then add add a little cold water?

Can you briefly or greatly explain how to

PLAN THE INVESTIGATON
Obtain evidence
analyse and consider evidence

thanks

2007-03-06 00:59:30 · 6 answers · asked by jewl 32 2