Physics - October 2007

You push a 34.4 kg crate at a constant speed of 1.66 m/s across a horizontal floor with coefficient of kinetic friction 0.34. The acceleration of gravity is 9.8 m/s^2.
a) At what rate is work being done on the crate by you? Answer in W.
b) At what rate is energy being dissipated by the frictional force? Answer in W.

2007-10-01 17:19:44 · 1 answers · asked by Ron108 1

varies from 0 N to 33.4 N as we stretch the spring by moving one end 7.06 cm from its unstressed position.
a) Find the force constant of the spring. Answer in N/m
b) Find the work done in stretching the spring. Answer in J.

2007-10-01 17:16:53 · 2 answers · asked by Ron108 1

2007-10-01 17:15:29 · 3 answers · asked by sweets 1

My friend and I were talking one day, we where coming up with theories how God communicated with humans. One of the things I said if thought is a form of energy the one person can send thoughts to another. I was wondering if thought if a form of energy NOT that it uses energy.

2007-10-01 17:09:26 · 5 answers · asked by acdc 2

We were asked to graph results from an experiment dealing with a projectile, and we were asked to make the X axis velocity and the Y axis distance. There are then questions about slope and time. As far as I can tell, T=v/x from the original equation, x/t=v. I find nothing about the equation flipped. I am also sure that the last time I checked, slope is rise (Y) over run (X). Is there a good reason for this madness or is he the nutty professor?

2007-10-01 16:56:08 · 4 answers · asked by scripta_elegans 2

does anyone know

the relationship between acceleration
and net force?

and the relationship between acceleration and mass?

2007-10-01 16:45:39 · 2 answers · asked by 123456 2

A child slides down a slide with a 20° incline, and at the bottom her speed is precisely one-fourth what it would have been if the slide had been frictionless. Calculate the coefficient of kinetic friction between the slide and the child

2007-10-01 16:44:58 · 2 answers · asked by xxzeroennaxx 1

I am looking for the name of the object that floats below the water surface but does not sink

2007-10-01 15:54:14 · 1 answers · asked by chewy_95 2

2007-10-01 15:53:27 · 1 answers · asked by Anonymous

For which one of the following situations will the pat length equal the magnitude of the displacement?
a)a jogger is running around a circular pth.
b) A ball is rolling down an inclined plane.
c) A train travels 5 miles east; and then, it stops and travels 2 miles west.
d) A ball rises and falls after being thrown straight up from the earth's surface.
e) a ball on the end of a string is moving in a vertical circle.

I'd rather you explain then give the answer....well if you'd be so kind...........thanks!!

2007-10-01 15:18:38 · 1 answers · asked by Anonymous

What is the minimum number of vectors with UNEQUAL magnitudes whose vector sum can be zero?

help please!

a)two
b)three
c)four
d)five
e)six

2007-10-01 15:15:38 · 6 answers · asked by Anonymous

i gota 45 Hz waveform and 10V voltage and im trying to find the change in phase between the current and voltage across capacitor..... Whats the formula for this????? I know its simple but I cant find it in my notes....... Is it simply 90 deg?

2007-10-01 14:48:25 · 1 answers · asked by james m 3

A block of mass 500. g is sliding on a rough surface with an initial speed of 1.4 m/s. It comes to a rest after a time of 0.70 s. What is the coefficient of kinetic friction

2007-10-01 14:38:34 · 5 answers · asked by Anonymous

A woman rides on a Ferris wheel of radius 16 that maintains the same speed throughout its motion. To better understand physics, she takes along a digital bathroom scale (with memory) and sits on it. When she gets off the ride, she uploads the scale readings to a computer and creates a graph of scale reading versus time. Note that the graph has a minimum value of 510 and a maximum value of 666 .

2007-10-01 14:11:24 · 1 answers · asked by smart-crazy 4

A pitcher throws a baseball horizontally from the mound to home plate. The ball falls 0.987 m (3.24 ft) by the time it reaches home plate 18.3 m (60 ft) away. How fast was the pitcher's pitch?

2007-10-01 14:07:01 · 2 answers · asked by sumanth s 1

time vs. position
0--------------- 0
2----------------4
4---------------6.5
6---------------8.5
8---------------14
10-------------14
12-------------14
14-------------14
16-------------14
18-------------14
20-------------14
22-------------11
24------------ 6.2
26-------------0

Try to use the graph above

calculate the average acceleration for the time period t=8 & t=10

draw a vector to show this acceleration

suppose that there is a passenger of mass 70kg in the elevator calculate the apparent weight of the passenger at t=4s

2007-10-01 14:02:24 · 1 answers · asked by Kyle 1

A skier is accelerating down a 30 degree hill at 3.80 m/s^2. What is the vertical component of her acceleration? How long will it take her to reach the bottom off the hill, assuming she starts from rest and accelerates uniformly, if the elevation change is 335 m. Please show/explain work clearly.

2007-10-01 13:45:05 · 1 answers · asked by nirmal 1

...acceleration of 1.8m/s/^2.
The car makes it 0.6 of the way around the circle before skidding off the track.
acceleration of gravity=9.8m/s^2
What is the coeffcient of static friction between the car and track??

2007-10-01 13:21:18 · 1 answers · asked by michael 1

1) Sometimes people say that water is removed from clothes in a spin dryer by centrifugal force throwing the water outward. What is wrong with this statement?

2) A bucket of water can be whirled in a vertical circle without the water spilling out, even at the top of a circle when the bucket is upside down. Explain.

plz help.... :)

2007-10-01 13:17:05 · 1 answers · asked by Anonymous

Accel. of gravity = 9.8m/s^2
What is the Net centripetal force needed to keep the car from skidding sideways?

If there were no friction between the car's tires and road, what would be the centripetal force provided just by the banking of the road??

Suppose the friction force is sufficient to keep the car from skidding. whats the magnitude of the Normal force exerted on the car by the road's surface???

What is the Magnitude of the Friction Force?

And what could be the lowest possible value of the static friction coeffcient that would prevent the car from skidding?


please help!

2007-10-01 13:13:26 · 1 answers · asked by michael 1

A simular question has already been asked in a now closed forum, however I didn't get the answer I was looking for out of it. Some of the statements made in the previous forum were "a mach is passing the sound barrier and light doesn't have a barrier" Well light may not have a barrier (as seen yet) but we continue to say mach even though mach 2,3,4... doesn't create a sonic boom. The second statement was that nothing is faster than the speed of light, well we're assuming there is or could be. So that being said, I'm looking for a dictionary answer of what you would call the speed of light multiplied by x. If you want to include the medium in which it's traveling, we'll say the vacuum of space without a spec of matter around. I did a small amount of research to figure this question out and I found no answer. So if it becomes a word I say we call it a Spock, cause it rhymes with Mach and would please the trekies, no that's a joke of course. There has to already be a word for it.

2007-10-01 12:40:15 · 2 answers · asked by atheist7775 1

2007-10-01 12:34:20 · 3 answers · asked by Jack 1

A car traveling at 91 km/h strikes a tree. The front end of the car compresses and the driver comes to rest after traveling 0.89 m. What was the average acceleration of the driver during the collision? Express the answer in terms of "g's," where 1.00g = 9.80 m/s2
g

2007-10-01 12:32:01 · 2 answers · asked by Daydreamer 3

If you add the denominator 3 to both the numerator and the denominator of the fraction 1/3 , the value of the fraction will double. Find a fraction that will triple the value when its denominator is added to its numeration and to the denominator.

2007-10-01 11:48:12 · 1 answers · asked by grazy76 1

Please tell me the difference.

2007-10-01 11:46:46 · 9 answers · asked by Anonymous

who invented the thermometer

2007-10-01 11:31:16 · 6 answers · asked by Anonymous

4.00 cm2 in cross-sectional area. A) Determine the elongation of the cable. B) By what additional amount does the cable increase in length if the object is accelerated upward at a rate of 3 m/s2? C) What is the greatest mass that can be accelerated upward at 3 m/s2 if the stress in the cable is not to exceed the elastic limit of the cable, 2.2 x 108 Pa?

I've worked out the problems below but I'm not sure if I did the calculations correctly. If you see an blatant errors, please point them out. Thank you :)

A) F/A= Y(Change in L)/ L
800 kg = 7840 N
7840 N/ 4 x 10^-4 m^2 = (20 x 10^10 Pa)(change in L)/ 25.0 m
Change in L = 2.45 mm
B) F=(mass)(acceleration)
F=(3.0 m/s^2)(800 kg) = 2400 N
F/A= Y(Change in L)/ L
2400 N/ 4 x 10^-4 m^2 = (20 x 10^10 pa)(change in L)/ 25 m
change in L = 0.75 mm
C) F=mass x acceleration
F= (3.0 m/s^2)m
F/A = 2.2 x 10^8 Pa
(3.0 m/s^2)m / (4 x 10^-4 m^2) = 2.2 x 10^8 Pa
m = 29333.3 kg

2007-10-01 10:53:40 · 2 answers · asked by Diff 1

n elevator (cabin mass 570 kg) is designed for a maximum load of 2300 kg, and to reach a velocity of 3.5 m/s in 3 s. For this scenario, what is the tension the elevator rope has to withstand?

2007-10-01 10:50:07 · 1 answers · asked by jULIAN C 2

2007-10-01 10:47:37 · 5 answers · asked by Anonymous

Given t1/2 to be 0.0133 seconds, how long should it take to reach 87.5% of maximum charge?
time = _________________seconds.
(Answer with three significant figures or N/A if there is no answer.)

please help and explain how to do this, thanks

2007-10-01 10:43:37 · 1 answers · asked by Anonymous