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April 18, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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physics
mvi^2=kxf k=mvi^2 / xf2 k=(5.00*105)(0.5)^2 / (0.4) k=328 N/m
Tuesday, April 1, 2014 at 5:58pm

Physics
@Damon what happens to the sin component of the centripetal force?
Tuesday, April 1, 2014 at 5:57pm

Algebra II
just plug in your value: 24.2 = √(19.6 h) √h = 24.2/√19.6 h = (24.2/√19.6)^2 = 29.88 m or I know from physics that h = 4.905 t^2 gives you the height from which an object was dropped after t seconds , and v = 9.81 t gives you the velocity after t ...
Tuesday, April 1, 2014 at 5:52pm

physics
What is the smallest size plane mirror a 184-cm {\rm cm}-tall person should buy to see himself if he mounts the mirror on a vertical wall?
Tuesday, April 1, 2014 at 5:05pm

Physics
After a completely inelastic collision, two objects of the same mass and same initial speed are found to move away together at 1/5 their initial speed. Find the angle between the initial velocities of the objects.
Tuesday, April 1, 2014 at 4:55pm

Physics
A stone is dropped at t = 0. A second stone, with 4 times the mass of the first, is dropped from the same point at t = 110 ms. (a) How far below the release point is the center of mass of the two stones at t = 410 ms? (Neither stone has yet reached the ground.) (b) How fast is...
Tuesday, April 1, 2014 at 4:44pm

physics
A certain hydraulic system is designed to exert a force 100 times as large as the one put into it. (a) What must be the ratio of the area of the slave cylinder to the area of the master cylinder? (b) What must be the ratio of their diameters? (c) By what factor is the distance...
Tuesday, April 1, 2014 at 4:26pm

Physics needs help
Indicate your specific subject in the "School Subject" box, so those with expertise in the area will respond to the question.
Tuesday, April 1, 2014 at 2:10pm

physics
A concrete wall of thickness one metre of a dam can withstand a side pressure of 10 5 2 N m- . Find the thickness of sidewall at the bottom of the water dam at a depth of 100 m. [ g = - 10 m 2 s and density of water = 10 3 kg/m3 ]
Tuesday, April 1, 2014 at 1:35pm

physics
avgspeed=distance/time time= 20/60 + 20/80 hrs=1/3 + 1/4 hr = 7/12 hr distance=40 km
Tuesday, April 1, 2014 at 10:33am

physics
A train travel 20km at a uniform speed 60km/1hr and the next 20km at a uniform speed of 80km/1hr calculate its average speed
Tuesday, April 1, 2014 at 8:53am

Physics Help
You have: velocity v = dx/dt = -A*ω*sin(ωt) so what is -A omega ? A = 3.5 omega = 2 pi f = .848 so - A omega = -2.968 or -2.97
Tuesday, April 1, 2014 at 5:04am

Physics
r = 1.5 * 10^-3 m pi r^2 = pi (2.25) * 10^-6 m^2 F/A = P = 2*10^4 /[pi (2.25) *10^-6) ] = .283 *10^10 = 2.83 * 10*9 Pascals
Tuesday, April 1, 2014 at 5:00am

Physics
What pressure is exerted by the tip a nail struck with a Force of 20,000N? Assume the tip is a 1.5mm-radius circle.
Tuesday, April 1, 2014 at 2:58am

Physics
Finally was able to solve this myself, but still need help understanding my other question.
Tuesday, April 1, 2014 at 2:50am

Physics Help
A bungee jumper undergoes simple harmonic motion with amplitude 3.5 m and frequency 0.135 Hz. Assume the bungee jumper follows the simple harmonic motion equation x=Acos(wt). A. Determine the bungee jumper's velocity at 0.25 s B. Determine the bungee jumper's velocity ...
Tuesday, April 1, 2014 at 1:33am

Physics
A puck with mass m = 0.17kg slides along a frictionless horizontal surface at v = 5.3m/s . It hits and sticks to the free end of a spring with k = 17N/m Find the amplitude and period of the subsequent simple harmonic motion?
Tuesday, April 1, 2014 at 12:53am

Physics
2.3) The question says "range of speeds", so i was expecting a quadratic formula.( What do you mean by reversing mu?
Tuesday, April 1, 2014 at 12:28am

Need help on Physics!!
Three uniform spheres are fixed at the positions shown in the diagram. Assume they are completely isolated and there are no other masses nearby. (a) What is the magnitude of the force on a 0.20 kg particle placed at the origin (Point P)? What is the direction of this force? (b...
Monday, March 31, 2014 at 11:24pm

Physics please help ASAP!
If you know the mass of a star and a planet’s radius and speed at perihelion (closest approach to the star), then using conservation of energy and angular momentum you can solve for the radius and speed of that planet at aphelion (farthest point from the star). Encke’...
Monday, March 31, 2014 at 11:20pm

physics
The figure below shows a claw hammer being used to pull a nail out of a horizontal board where θ = 32.2°. The mass of the hammer is 1.00 kg. A force of 125 N is exerted horizontally as shown, and the nail does not yet move relative to the board. Assume the force the ...
Monday, March 31, 2014 at 11:08pm

Physics
A toy dart gun has a spring with a spring constant of 315 N/m. An 12 gram dart is loaded in the gun and the spring is compressed a distance of 7.8 cm and then shot into the air. When the dart is 5.8 meters high in the air, what is its speed? If the maximum height the dart can ...
Monday, March 31, 2014 at 11:00pm

Physics
Water flows into a house at a velocity of 15 m/s through a pipe that has a radius of 0.40 m. The water then flows through a smaller pipe at a velocity of 45 m/s. What is the radius of the smaller pipe?
Monday, March 31, 2014 at 10:30pm

Physics
How much pressure is exerted on a submarine at a depth of 8.50 km in the Pacific Ocean? (density of sea water = 1.025 x 10^3 kg/m3, P0 = 1.01 x 10^5 Pa)
Monday, March 31, 2014 at 10:24pm

Physics
The two pistons in a hydraulic lift have radii of 2.67 cm and 20.00 cm respectively. What force must be applied to the 2.67 cm piston so that a 2.0 x 10^3 kg mass resting on the 20.0 cm piston is lifted?
Monday, March 31, 2014 at 10:22pm

Physics
The two pistons in a hydraulic lift have radii of 2.67 cm and 20.00 cm respectively. What force must be applied to the 2.67 cm piston so that a 2.0 x 103 kg mass resting on the 20.0 cm piston is lifted?
Monday, March 31, 2014 at 10:21pm

Physics
Rn-222
Monday, March 31, 2014 at 10:18pm

Physics
What element results if two protons and two neutrons are ejected from a radium nucleus?
Monday, March 31, 2014 at 10:10pm

physics
A string with a length of 1.3 m is fixed at both ends. What is the longest possible wavelength for a standing wave on this string?
Monday, March 31, 2014 at 10:05pm

physics
A person is standing in an elevator, which is accelerating upwards. What can you say about the relationship between the force due to gravity mg and the normal force N (both on the person)? a) N > mg b) N = mg c) N < mg (but not zero) d) N = 0 I picked d because the m in ...
Monday, March 31, 2014 at 10:04pm

college physics 2
A healthy astronaut's heart rate is 60 beats/min. Flight doctors on Earth can monitor an astronaut's vital signs remotely while in flight. How fast would an astronaut be flying away from Earth if the doctor measured her having a heart rate of 28 beats/min?
Monday, March 31, 2014 at 9:48pm

physics
sum moments about the top of the ladder. Is this a weightless ladder? the ladder weight is not given. clockwise positive, and my sketch has clockwise toward the wall. d is the distance from base to wall Theta is the base angle, so d/5.7=sinTheta sum moments about the top wall ...
Monday, March 31, 2014 at 9:33pm

physics
2PI*freq= sqrt (k/m) a. the mass on each spring is 1150/4, (2PI*2.2)^2*1150/4= k b. freq= 1/2PI * sqrt (kabove/(( 1150/4 + 80)
Monday, March 31, 2014 at 9:23pm

physics
It seems to me she will be slamming into the wall... There is not enough information here to give you an answer.
Monday, March 31, 2014 at 9:13pm

physics
Astronauts in space cannot weigh themselves by standing on a bathroom scale. Instead, they determine their mass by oscillating on a large spring. Supppose an astronaut attaches one end of a large spring to her belt and the other end to a hook on the wall of the space capsule. ...
Monday, March 31, 2014 at 8:26pm

physics
A compact car has a mass of 1150 kg. Assume that the car has one spring on each wheel, that the springs are identical, and that the mass is equally distributed over the four springs. (a) What is the spring constant of each spring if the empty car bounces up and down 2.2 times ...
Monday, March 31, 2014 at 8:17pm

physics
The acceleration due to gravity on the moon is 1.62 m/s2. What is the length of a pendulum whose period on the moon matches the period of a 4.00-m-long pendulum on earth?
Monday, March 31, 2014 at 7:47pm

physics
swag means ...secretly we are gay....so all u faggots stop saying it
Monday, March 31, 2014 at 7:26pm

physics
A ladder can fall for two reasons. If it is set too steep and the climber gets their mass to the left of the ladder's base, the ladder likely will fall over backwards. If the ladder is set at too shallow of an angle the required force of friction between the ladder and ...
Monday, March 31, 2014 at 7:09pm

Physics
A 3000N force stretches a wire by 2.0mm. A second wire of the same material is twice as long and has twice the diameter. How much force is needed to stretch it by 1.0 mm?
Monday, March 31, 2014 at 4:13pm

Physics
5 m/s
Monday, March 31, 2014 at 3:15pm

physics
For a hydrogen atom, determine the ratio of the ionization energy for the n = 3 excited state to the ionization energy for the ground state.
Monday, March 31, 2014 at 3:10pm

physics
Light shines through a single slit whose width is 5.7 × 10-4 m. A diffraction pattern is formed on a flat screen located 4.0 m away. The distance between the middle of the central bright fringe and the first dark fringe is 3.9 mm. What is the wavelength of the light?
Monday, March 31, 2014 at 2:44pm

physics
A 148 kg student sits on a chair which is solely supported by a solid 0.97 meter-long steel rod 0.68 cm in diameter. What is the change in length of the rod produced by the student's weight? Delta l =
Monday, March 31, 2014 at 2:20pm

Physics
weight down = m g max friction force = mu m g centripetal force = m (lateral acceleration) mu m g = m a = m (.96 g) a = .96 g We call "lateral acceleration" centripetal acceleration :)
Monday, March 31, 2014 at 1:22pm

physics
Because the air we live in also has pressure no pressure change in a horizontal hose with no flow through it.
Monday, March 31, 2014 at 1:01pm

Physics
@Damon: I don't understand why that is the answer for 2.1
Monday, March 31, 2014 at 1:00pm

Physics
2.1) LOL - I would guess around mu = 0.96 2.2) 120,000 m/h * 1 h/3600 s = 33.33 m/s m v^2/R = .96 m g R = v^2/(.96 g) = 118 meters 2.3) mu = .8*.96 = .768 Normal F = m g cos 15 = .966 m g friction force = mu Normal = .768*.966mg =.742 mg component of weight down slope = m g ...
Monday, March 31, 2014 at 12:53pm

Physics
You are welcome :)
Monday, March 31, 2014 at 12:17pm

Physics
I need to check my answers for the following: An Aston Martin V8 Vantage sports car has a maximum “lateral acceleration” of 0.96 “g’s”, after which the car begins to skid out of its turn. 2.1 Calculate the coefficient of static friction between the car...
Monday, March 31, 2014 at 12:08pm

Physics
thank you very much ! i got it half the way but couldnt figure out how to finish it .
Monday, March 31, 2014 at 11:58am

Physics
ke of ball at bottom = (1/2) m (2.44)^2 = 2.98 m Pe at top = m g h = m (9.81)(h) so 9.81 h m = 2.98 m h = .303 meters h = 1.47 (1 - cos theta) .303/1.47 = 1 - cos T .206 = 1 - cos T -cos T = -.794 T = 37.4 degrees
Monday, March 31, 2014 at 11:39am

physics
(1/2)(4.008) V^2 = (1/2)(2500)(.037)^2 V = .924 m/s .008 Vb = (4.008)(.924 ) Vb = 463 m/s
Monday, March 31, 2014 at 11:33am

Physics
A steel ball hangs in a 147cm thread which is dragged right and then let go. Velocityh of the ball is 2,44m/s when it goes through the middle position. I dont have any mass given up. How many degrees to the side had the ball been dragged?
Monday, March 31, 2014 at 11:12am

physics
That gives me an answer of 4625.93 m/s. The correct answer is 460 m/s. Can you tell me what I did wrong? I found V=.925 m/s, then did m1v1=m2v2.
Monday, March 31, 2014 at 11:02am

physics
use conservation of momentum to get the velocity of the total mass (4.008 kg) just after collision in terms of bullet velocity Vb. Call that V. (1/2) m V^2 = (1/2) k x^2 that gives you V go back and get Vb
Monday, March 31, 2014 at 10:11am

physics
Actually, can you do this anyway?
Monday, March 31, 2014 at 10:03am

physics
Nevermind. Disregard this post.
Monday, March 31, 2014 at 9:38am

physics
If you could just tell me the steps and equations to use, without the numbers, that would be great. Thank you again in advance
Monday, March 31, 2014 at 9:37am

physics
An 8 g bullet is shot into a 4.0 kg block, at rest on a frictionless horizontal surface. The bullet remains lodged in the block. The block moves into a spring and compresses it by 3.7 cm. The force constant of the spring is 2500 N/m. In the figure, the initial velocity of the ...
Monday, March 31, 2014 at 9:36am

physics
Why do you need to add the 1 atm? And the 2 cm in this question does not matter?
Monday, March 31, 2014 at 9:27am

physics
Thank you boss!
Monday, March 31, 2014 at 9:25am

Physics
weight in air = 6400 * 9.81 volume of water displaced = 1 m^3 weight of water displaced = 1000 *9.81 *1 = 9810 N = force up from water tension = (6400 - 1000)(9.81) = 52,974 N
Monday, March 31, 2014 at 8:43am

Physics
(1/2) m v^2 = .5 * .559 * 2.7^2
Monday, March 31, 2014 at 8:39am

physics
a) v^2/R b) m v^2/R
Monday, March 31, 2014 at 8:37am

physics
2000 u = 10 (200 cos 60 ) u = cos 60
Monday, March 31, 2014 at 8:36am

physics
1500 * 20 = (1500+m)10 m = 1500
Monday, March 31, 2014 at 8:35am

physics
rho g h = 1000 (9.81)(30) = 2.94*10^5 add 1 atm = 1*10^5 and get total of 3.9 * 10^5
Monday, March 31, 2014 at 8:32am

Physics
Yep, it was a bit confusing, but I just looked at what he was doing and used my numbers.
Monday, March 31, 2014 at 7:56am

Physics
A cubic meter of some material has a mass of 6400 kg. The block of material is lowered into a lake by a strong cable until the block is completely submerged. Draw a free-body diagram for the block. (Do this on paper. Your instructor may ask you to turn in your work.) Find the ...
Monday, March 31, 2014 at 6:34am

Physics
A 0.559 kg particle has a speed of 2.7 m/s at point A and kinetic energy of 8.4 J at point B. What is its kinetic energy at A?
Monday, March 31, 2014 at 5:56am

physics
F = GmM/r^2 2.5*10^-10 = 6.674*10^-11 * x(4-x) / .25^2 x = 0.059 4-x = 3.941 Must be a bowling ball and a ping pong ball
Monday, March 31, 2014 at 5:44am

physics
lll
Monday, March 31, 2014 at 3:14am

physics
car with a mass of 1280 kg is moving around a curve with a radius of 50 m at a constant speed of 10 m/s (about 22 MPH). (a) What is the centripetal acceleration of the car? (b) What is the magnitude of the force required to produce this centripetal acceleration
Monday, March 31, 2014 at 2:41am

Physics
I need immediate help on these questions:. 2.a small plastic ball with a mass of 0.005kg is suspended from a thread and hangs in equilibrium as shown in the drawing below when a small rod with a 2 uC charge is brought to within 3mm of the ball a)find the tension force in the ...
Sunday, March 30, 2014 at 11:55pm

Physics
You understand that he used quite different numbers in his example, D = 2.71 diameter 24 liters instead of 25 1.1 instead of 1.4 min
Sunday, March 30, 2014 at 11:24pm

Physics
I found it all right. He has a pretty convoluted way of explaining it but it is the same thing. I have no idea why he converted to cm^3 rather than to meters^3 from Liters 1000 Liters = 1 m^3 1 Liter = 1000 cm^3 1 m^3 = 1,000,000 cm^3 but it is standard to work in meters, kg ...
Sunday, March 30, 2014 at 11:21pm

physics
a cannon with mass of 2,000 kg fires a 10 kg shell with a velocity of 200 m/s at an angle of 60 degrees above the horizontal. What is the recoil velocity of the cannon across the level ground?
Sunday, March 30, 2014 at 11:13pm

physics
a 1500 kg car moving at 20 m/s strikes a truck waiting at a traffic light, hooking the bumpers. The two continue to move together at 10 m/s. What was the mass of the truck?
Sunday, March 30, 2014 at 11:11pm

physics
A water tank is filled to a depth of 10 m and the tank is 20 m above ground. The water pressure at ground level in a hose 2 cm in diameter is closest to: A) 3.9 × 105 N/m2 B) 2.0 × 104 N/m2 C) 9.2 N/m2 D) The cross-sectional area of the tank is needed.
Sunday, March 30, 2014 at 11:09pm

Physics
It's called Mike's Online Biology: MOB University. Click physics Tutoring tab -> chapter 9 -> scroll down to question #13 with video below it. I used it as a guide.
Sunday, March 30, 2014 at 10:55pm

physics
two objects attract each other gravitationally with a force of 2.5^-10N.when they are 0.25m apart. Their total mass is 4.00kg. Find the individual mass?
Sunday, March 30, 2014 at 10:52pm

physics
work done = change in Ke = (1/2) m v^2 = 500*900 Joules power = work/time = 500 * 900 / 5 = 90,000 Watts
Sunday, March 30, 2014 at 10:38pm

physics
a 1000 kg sports car accelerates from 0-30 m/s in 5.0 s. What is tge average power delivered by the automobile engine?
Sunday, March 30, 2014 at 10:34pm

physics
Imagine having an 80-turn coil with radius of 5.0 cm and resistance of 30 Ù. At what rate must a perpendicular magnetic field change to produce a current of 4.0 A?
Sunday, March 30, 2014 at 9:49pm

ap physics b
poop :)
Sunday, March 30, 2014 at 9:48pm

physics
A uniform magnetic field makes an angle of 30 degrees with the axis of a circular loop of 300 turns and radius of 4 cm. The magnetic field changes at a rate of 85 T/s. Determine the magnitude of the induced emf in the loop.
Sunday, March 30, 2014 at 9:48pm

physics
dsdf
Sunday, March 30, 2014 at 9:42pm

Physics
What is the mass of the crate?
Sunday, March 30, 2014 at 8:18pm

Physics
ok. Should I post it again?
Sunday, March 30, 2014 at 8:17pm

Physics
You are welcome :) Good luck. Come back and tell me when you find out.
Sunday, March 30, 2014 at 8:15pm

Physics
I know the flow rate is the speed times the area. That is my field :)
Sunday, March 30, 2014 at 8:12pm

Physics
Thanks for helping!!
Sunday, March 30, 2014 at 8:11pm

Physics
I can not find an error. I hope one of the other math/physics teachers finds something.
Sunday, March 30, 2014 at 8:10pm

Physics 112
a) as t--> oo inductor is a short circuit, no reactance so V = i at big t * R V = (8.4)(.26) = 2.14 Volts b) at t = 0, i = 0, so all voltage across L 2.14 = L di/dt let i = 8.4 [ 1 - e^-t/tau ] given tau = .1 s i = 8.4 [ 1 - e^-10 t ] di/dt = 8.4 (10 e^-10 t) di/dt = 84 at ...
Sunday, March 30, 2014 at 8:08pm

Physics
The conversions are correct and I'm getting the same answer using your method, but it's still saying that they are incorrect. Sorry for bothering you so much...
Sunday, March 30, 2014 at 7:58pm

Physics 112
A battery is connected in series with a R = 0.26 Ω resistor and an inductor, as shown in the figure below. The switch is closed at t = 0. The time constant of the circuit is τ = 0.10 s, and the maximum current in the circuit is I = 8.4 A. Find the following. (a) the ...
Sunday, March 30, 2014 at 7:51pm

Physics
call 41.18 41.2 maybe, sometimes they fuss about their round off rules.
Sunday, March 30, 2014 at 7:50pm

Physics
Well, it is their word against mine I guess, but check my arithmetic and units carefully Physics - Damon, Sunday, March 30, 2014 at 7:21pm 25 L = 25 * 10^-3 m^3 2.77 cm = .0277 m 1.4 min = 84 seconds flow rate * time = amount pi r^2 v * 84 = .025 m^3 pi (.0139)^2 v = .025 v = ...
Sunday, March 30, 2014 at 7:48pm

Physics
I'm not trying to be mean or anything. The WebAssign website said the answers was wrong.
Sunday, March 30, 2014 at 7:46pm

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