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April 21, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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physics
A 20kg block is initially at rest on a rough, horizontal surface. A horizontal force of 75N is required to set the block in motion. After it is in motion, a horizontal force of 60N is required to keep the block moving with constant speed. Find the coefficient of static and ...
Thursday, March 6, 2014 at 5:27pm

Physics
A 56 kg swimmer jumps off of 15 m tower. Find the swimmers velocity when hitting the water.
Thursday, March 6, 2014 at 5:22pm

Physics
Thank you, I now understand it.
Thursday, March 6, 2014 at 5:09pm

Physics
The maximum emf induced in a 10 turn coil with a cross sectional area of 0.1m squared rotating at 20 rad/s in a uniform 10 Tesla magnetic field is _________.
Thursday, March 6, 2014 at 5:01pm

physics
An iron bar of mass, 0.6 kg, slides down a frictionless incline 0.38 m high. At the bottom of the incline it collides and sticks to a magnet of mass, 0.94 kg. What is the speed of the combined masses after collision.
Thursday, March 6, 2014 at 4:52pm

Physics
660
Thursday, March 6, 2014 at 3:20pm

Physics
A string going over a massless frictionless pulley connects two blocks of masses 6.4 kg and 13 kg. As shown on the picture below, the 6.4 kg block lies on a 32◦ incline; the coefficient of kinetic friction between the block and the incline is μ= 0.3. The 13 kg block...
Thursday, March 6, 2014 at 3:12pm

Physics
1. Two blocks on a frictionless horizontal surface are connected by a light string. where m1 = 6.21 kg and m2 = 19.5 kg. A force of 48.4 N 6.21kg --T-- 19.5kg ----->48.4 N The acceleration of gravity is 9.8 m/s^2. Find the acceleration of the system. Answer in units of m/s^...
Thursday, March 6, 2014 at 3:08pm

physics? math?
.
Thursday, March 6, 2014 at 3:06pm

physics
A smooth block is released at an angle of 30 degree incline & then slide distance d. The time taken is 'x' times as much to slide on rough inclined plane than on smooth inclined. Then what is coefficient of friction?
Thursday, March 6, 2014 at 2:20pm

Math Help
I have to do this question in several ways like any possible way to do it so I've found one mathematical way, I can't do it like a physics question cause it's math. a bike travels at a constant speed of 10km/h. a bus starts 175 km behind the bike and catches up to ...
Thursday, March 6, 2014 at 2:17pm

physics
A string going over a massless frictionless pulley connects two blocks of masses 4.4 kg and 11 kg. As shown on the picture below, the 4.4 kg block lies on a 23◦ incline; the coefficient of kinetic friction between the block and the incline is μ = 0.29. The 11 kg ...
Thursday, March 6, 2014 at 1:24pm

physics multiple choice
ui;
Thursday, March 6, 2014 at 12:03pm

physics
normal force = m g cos 45 so friction down slope = .3 m g cos 45 at 45 sin 45 = cos 45 = sqrt 2/2 weight down slope = m g sin 45 15 N = m g sin 45 + .3 m g cos 45 15 N = (m g sqrt 2/2)( 1 + .3) 30/1.3 sqrt 2 = m g = weight if friction he other way then F up = (m g sqrt 2/2)( 1...
Thursday, March 6, 2014 at 11:14am

physics
a block moves up 45degree incline w/ constant speed under the action of a force of 15n applied parallel to the incline.If the coefficient of kinetic friction is 0.3, determine the weight of the block and minimum force required to allow the block to move down the incline at ...
Thursday, March 6, 2014 at 9:41am

Physics
you have distance, time horizonal velocity=horizontaldistance/time = 60/3.6 m/s
Thursday, March 6, 2014 at 8:18am

Physics
A rock is thrown off a bridge at an angle of 38degree above horizontal, and landed in the water 3.60 seconds later 60.0 meters from the point at the waters level directly below the thrower... What is the rock's horizontal velocity? I need better clarity on physics, please?
Wednesday, March 5, 2014 at 11:47pm

physics
1. A ship has a top speed of 3.0 m/s in calm water. The current of the ocean tends to push the boat at 2.0 m/s on a bearing of due South. What will be the net velocity of the ship if the captain points his ship on a bearing of 55 North or West and applies full power?
Wednesday, March 5, 2014 at 11:41pm

Physics
A superball with a mass of 71.2 g is dropped from a height of 2.5 m. It rebounds to a height of 2 m. What is the change in its linear momen- tum during the collision with the floor? The acceleration of gravity is 9.8 m/s2 . Answer in units of kg · m/s
Wednesday, March 5, 2014 at 11:05pm

physics
what is the physics behind the process of administering the following 1. measurement of blood pressure using sphygmomanometer 2.giving injections 3.administering intravenous infusion 4.giving oxygen in the ward and operating theater 5. administering blood transfusion 6.sucking...
Wednesday, March 5, 2014 at 11:04pm

Physics
F = m*g = 0.05kg * 9.8N/kg = 0.49 N. d = 18-12 = 6 cm = 0.06 m. k = 0.49N/0.06m = 8.17N/m.
Wednesday, March 5, 2014 at 10:40pm

Physics
After a 0.200-kg rubber ball is dropped from a height of 1.95 m, it bounces off a concrete floor and rebounds to a height of 1.45 m. (a) Determine the magnitude and direction of the impulse delivered to the ball by the floor. (b) Estimate the time the ball is in contact with ...
Wednesday, March 5, 2014 at 9:29pm

Physics
If m1 = 4.72kg, what mass m2 is required to balance the system? (two masses are connected by a rope. m1 is sitting on an incline and m2 is hanging from a pulley)
Wednesday, March 5, 2014 at 8:53pm

Physics
distance engineer moved = 500 m = .5 km average speed = (84.2 +16.4)/2 = 50.3 km/hr (during constant acceleration you can use the average of first and last for the distance and time) time = distance/speed = .5km / 50.3 km/hr = .00994 hours * 3600 = 35.8 seconds
Wednesday, March 5, 2014 at 8:51pm

Physics
charge has no effect on mass
Wednesday, March 5, 2014 at 8:39pm

Physics
m g down mu m g friction force F = m a mu m g = m a a = mu g = .4 (9.81) = 3.92 m/s^2 a = change in speed/time change in speed = v average speed during stop = v/2 distance = average speed * time 5 meters = v/2 t so t = 10/v a = v /(10/v) = v^2/10 so v^2/10 = 3.92 v^2 = 39.2 v...
Wednesday, March 5, 2014 at 8:38pm

Physics
A train 500 m long is moving on a straight track with a speed of 84.2 km/h. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 16.4 km/h. Assuming constant acceleration, determine how long the train blocked the crossing....
Wednesday, March 5, 2014 at 8:34pm

Physics
If the spherical ball is negatively charged.How the mass of the sphere or ball get effected?
Wednesday, March 5, 2014 at 8:26pm

Physics
A 0.80 10^3 kg Toyota collides into the rear end of a 2.6 1^03 kg Cadillac stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 5.0 m before stopping. The police officer, knowing that the coefficient of kinetic friction between tires ...
Wednesday, March 5, 2014 at 8:20pm

Physics
D= mass times volume Think of it as a pie shape so density is on top and mass and volume is on the bottom.... so you have to times 85 and 550 to get 382850 g/cm3
Wednesday, March 5, 2014 at 8:08pm

Physics
You look it up.
Wednesday, March 5, 2014 at 7:56pm

Physics
so in my head I am supposed to have stored the Young's modulus of steel ? delta L/L = tensile stress/E or delta L = F L /(E A) F = 4700 N A = (pi/4) .005^2 meters^2 L = 1.2 meters E = you look it up
Wednesday, March 5, 2014 at 7:54pm

Physics
A piece of metal has a mass of 85 cg and a volume of 450L. What is it's density in g/cm3?
Wednesday, March 5, 2014 at 7:48pm

Physics
A 1.2m -long steel rod with a diameter of 0.50cm hangs vertically from the ceiling. An auto engine weighing 4.7kN is hung from the rod. By how much does the rod stretch?
Wednesday, March 5, 2014 at 7:46pm

Physics
F = G M m/r^2 = m Ac so Ac = G M/r^2 G = 6.67 * 10^-11 M = 6 * 10^24 kg Copy this 4175 miles = meters into a Google search box and get r = 6.72*10^6 meters and 90 minutes is 5,400 seconds
Wednesday, March 5, 2014 at 7:46pm

Physics
acceleration= v^2/r= = (2pir/period)^2/r= 2PI*(r)/period^2 no change 90 min to seconds, and 4175 miles to meters, and you have it.
Wednesday, March 5, 2014 at 7:44pm

Physics
length= 10ft(12in/ft)(2.54cm/in) do the math.
Wednesday, March 5, 2014 at 7:42pm

Physics
how many centimeters long is the proverbial "10-foot pole?"
Wednesday, March 5, 2014 at 7:38pm

Physics
There is no horizontal force. Therefore the horizontal velocity REMAINS CONSTANT v = - g t = -9.81*5 = 49 m/s down
Wednesday, March 5, 2014 at 7:34pm

Physics
A satellite that is 4175 miles from the center of the earth, orbits with a period of 90 minutes. What is its centripetal acceleration?
Wednesday, March 5, 2014 at 7:32pm

Physics
You throw a ball horizontally off a building with a horizontal velocity of 10m/s. What is the ball's horizontal velocity 5 seconds later. What is the ball's vertical velocity 5 seconds later?
Wednesday, March 5, 2014 at 7:25pm

physics
F = G M m /d^2 6.67*10^-11*7.8*10^23*2.5*10^4/57.8*10^1​6 =2.25 * 10^0 = 2.25 N
Wednesday, March 5, 2014 at 7:13pm

Physics
for a more elaborate analysis see http://www.braeunig.us/space/propuls.htm​ read starting around equation (1.11)
Wednesday, March 5, 2014 at 7:05pm

Physics
initial momentum = 4.6*10^4 * 6.3*10^3 = 29 * 10^7 kgm/s no external forces so that is the final momentum final momentum = ship mass m *7.84*10^3 + exhaust momentum exhaust mass = (4.6*10^4 - m) what is the exhaust speed? I assume that 4.86 * 10^3 is relative to the space ship...
Wednesday, March 5, 2014 at 6:52pm

physics
(1/2) m u^2 = m g (Hup - Hdown) so u = sqrt(2*9.81*.954) u is horizontal speed, does not change How long in the air? Well, how long to fall .256 m ? .256 = 4.9 t^2 solve for t, time in the air distance horizontal = d = u t
Wednesday, March 5, 2014 at 6:32pm

physics
A 25000 kg rock is located at a distance of 7.6 x 108 m away from a small planet of mass 7.8 x 1023 kg. What is the mutual force of attraction between these two
Wednesday, March 5, 2014 at 6:25pm

Physics
A spaceship with a mass of 4.60 10^4 kg is traveling at 6.30 10^3 m/s relative to a space station. What mass will the ship have after it fires its engines in order to reach a speed of 7.84 10^3 m/s? Assume an exhaust velocity of 4.86 10^3 m/s.
Wednesday, March 5, 2014 at 6:23pm

Physics
work in = potential energy stored = (1/2) k x^2 double x, four times the energy stored so four times the work in.
Wednesday, March 5, 2014 at 6:21pm

physics
A 1.80-kg block slides down a frictionless ramp.The top of the ramp is h1 = 1.21 m above the ground; the bottom of the ramp is h2 = 0.256 m above the ground. The block leaves the ramp moving horizontally, and lands a horizontal distance $d$ away. Calculate the distance d.
Wednesday, March 5, 2014 at 6:19pm

Physics
3/4 = .75 hour at 70 ---> 52.5 1/6 = .167 hr at 95 ---> 15.8 1/2 = .5 hr at 55 ---> 27.5 20/60 = .333 hr at 0 --> 0 total time = 1.75 hours total distance = 95.8 km so 95.8 km / 1.75 hr = 54.7 km/hour
Wednesday, March 5, 2014 at 6:18pm

Physics
Does it take twice the work to stretch a spring 2cm from its equilibrium position as it does to stretch it 1cm from its equilibrium position?
Wednesday, March 5, 2014 at 6:16pm

physics
Two blocks, each with a mass m = 0.400 kg, can slide without friction on a horizontal surface. Initially, block 1 is in motion with a speed $v$ = 1.20 m/s; block 2 is at rest. When block 1 collides with block 2, a spring bumper on block 1 is compressed. Maximum compression of ...
Wednesday, March 5, 2014 at 6:07pm

physics
4
Wednesday, March 5, 2014 at 5:47pm

physics
A dust particle carrying a charge of is 2 mm to the left of another dust particle carrying a charge of . Find the magnitude and direction of the elec- tric force on the first particle.
Wednesday, March 5, 2014 at 5:38pm

Physics*
222
Wednesday, March 5, 2014 at 5:36pm

Physics
Please help me with the following problem: Joe is on a cross-country trip from New York to Los Angeles. He drives for 45.0 min at 70.0 km/h, 10.0 min at 95 km/h, and 30.0 min at 55.0 km/h, and he spends 20.0 min eating lunch and buying gas. What is the average speed for this ...
Wednesday, March 5, 2014 at 5:26pm

physics
A block of mass m = 2.7 kg is released from rest at a height of H = 0.49 m on a curved frictionless ramp. At the foot of the ramp is a spring whose spring constant is k = 515.0 N/m. What is the maximum compression of the spring, x? B)After the spring reaches its maximum ...
Wednesday, March 5, 2014 at 4:50pm

Physics
initial momentum = 3.7 * 5 = 18.5 kg m/s mass after crash = 3.7 + 2.0 = 5.7 kg so 18.5 = 5.7 u u = 3.25 m/s which is the horizontal speed until it hits the floor. NOW I DO NOT BELIEVE that your table is 6.9 meters high so I will just outline the rest How long to fall h meters...
Wednesday, March 5, 2014 at 4:38pm

Physics - I am Confused
Also, why did you convert the minutes into seconds, but in fraction form? The home-school lesson did not teach me how to do that. I don't understand why you would turn it into a fraction, can you explain it to me?
Wednesday, March 5, 2014 at 4:31pm

Physics
In the figure below, a 3.7 kg box of running shoes slides on a horizontal frictionless table and collides with a 2.0 kg box of ballet slippers initially at rest on the edge of the table, at height h = 6.9 m. The speed of the 3.7 kg box is 5.0 m/s just before the collision. If ...
Wednesday, March 5, 2014 at 4:31pm

Physics
Okay, I get what you did, but is there other ways of doing this?
Wednesday, March 5, 2014 at 4:27pm

Physics
average velocity=distance/time distance=3/4*70+1/6*95 + 1/2*55 time= (45+10+30)/60 check my thinking. I get none of the answers.
Wednesday, March 5, 2014 at 4:10pm

Physics
work done by friction: (M+m)g*mu*distance KE after imact: 1/2 (M+m)*v^2 set them equal, solve for v just after impact. Now, use the conservation of momentum (M+m)V=mV' solve for V', the speed before the impact.
Wednesday, March 5, 2014 at 4:05pm

Physics
In order to convert a tough split in bowling, it is necessary to strike the pin a glancing blow as shown in Fig. 9-47. The bowling ball, initially traveling at 13.0 m/s, has four times the mass of a pin and the pin flies off at 80° from the original direction of the ball. ...
Wednesday, March 5, 2014 at 3:54pm

Physics
A 96.0-g wooden block is initially at rest on a rough horizontal surface when a 11.4-g bullet is fired horizontally into (but does not go through) it. After the impact, the block–bullet combination slides 6.5 m before coming to rest. If the coefficient of kinetic friction...
Wednesday, March 5, 2014 at 3:54pm

Physics
Please help me with the following problem: Joe is on a cross-country trip from New York to Los Angeles. He drives for 45.0 min at 70.0 km/h, 10.0 min at 95 km/h, and 30.0 min at 55.0 km/h, and he spends 20.0 min eating lunch and buying gas. What is the average speed for this ...
Wednesday, March 5, 2014 at 3:47pm

physics
north
Wednesday, March 5, 2014 at 1:50pm

science
physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, esp. as distinct from energy.
Wednesday, March 5, 2014 at 1:37pm

physics
F = G M m/R^2 = m v^2/R so v^2 = G M/R G = 6.67 * 110^-11 M = 6 * 10^24 Re = 6.38*10^6 meters Ra = 6.38*10^6 + .418*10^6 Rb = 6.38*10^6 + .731*10^6
Wednesday, March 5, 2014 at 11:10am

physics 1
F = G Mm/R^2 = m v^2/R v^2 R = G M = 6.67*10^-11 * 5.98*10^24 v^2 R = 39.9 * 10^13 v T = circumference = 2 pi R so R = v T/(2 pi) R = v [1.77*10^4/(2 pi)] R = 2.82*10^3 v so v^3 (2.82*10^3) = 39.9 * 10^13 v^3 = 14.1 * 10^10 = 141 * 10^9 v = 5.2 * 10^3 v = 5,200 m/s
Wednesday, March 5, 2014 at 11:05am

physics
I assume that a Mg is a "megagram, a term I have never heard before. In that case we have 4*10^6 grams which is 4,000 Kilograms 4,000 * 30 = 120,000 kg m/s south
Wednesday, March 5, 2014 at 10:52am

physics
What is the momentum of a 4 Mg semi truck going 30 m/s south?
Wednesday, March 5, 2014 at 10:40am

physics
Two satellites are in circular orbits around the earth. The orbit for satellite A is at a height of 418 km above the earth’s surface, while that for satellite B is at a height of 731 km. Find the orbital speed for (a) satellite A and (b) satellite B.
Wednesday, March 5, 2014 at 8:39am

physics 1
A satellite is in a circular orbit about the earth (ME = 5.98 x 1024 kg). The period of the satellite is 1.77 x 104 s. What is the speed at which the satellite travels?
Wednesday, March 5, 2014 at 8:35am

Physics
What exactly is Maggie's situation value? Which may perhaps not be as simple as QuotesChimp appears to discover. Calculating her unique problems looks easy, plus often it is. But occasionally issues aren't constantly as they seem initially. Say imagine if Maggie had ...
Wednesday, March 5, 2014 at 8:24am

physics
100j
Wednesday, March 5, 2014 at 6:57am

physics
7820N
Wednesday, March 5, 2014 at 6:30am

Physics
How do u solve the question?
Wednesday, March 5, 2014 at 5:31am

college physics 1
Reviewing Interactive Solution 5.46 will help in solving this problem. A stone is tied to a string (length = 1.29 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the string is nearly parallel to the ground. Next...
Wednesday, March 5, 2014 at 3:36am

college physics 1
A special electronic sensor is embedded in the seat of a car that takes riders around a circular loop-the-loop ride at an amusement park. The sensor measures the magnitude of the normal force that the seat exerts on a rider. The loop-the-loop ride is in the vertical plane and ...
Wednesday, March 5, 2014 at 3:35am

college physics 1
Two newly discovered planets follow circular orbits around a star in a distant part of the galaxy. The orbital speeds of the planets are determined to be 35.1 km/s and 63.3 km/s. The slower planet's orbital period is 6.74 years. (a) What is the mass of the star? (b) What ...
Wednesday, March 5, 2014 at 3:35am

physics
3
Wednesday, March 5, 2014 at 1:35am

physics
A DC circuit has a single battery of voltage V = 10.0 V attached to a resistor R = 100 Ohms. If the voltage is increased to 20.0 V, then by what factor does the power emitted by the resistor increase?
Wednesday, March 5, 2014 at 12:33am

Physics
Two children pull a third child on a snow saucer sled exerting forces F1 and F2 as shown from above in Figure 4.36. Find the acceleration of the 49.00-kg sled and child system. Note that the direction of the frictional force is unspecified; it will be in the opposite direction...
Tuesday, March 4, 2014 at 11:52pm

physics
A roller-coaster car of mass 1.80 103 kg is initially at the top of a rise at point circle a. It then moves 40.8 m at an angle of 50.0° below the horizontal to a lower point circle b. (a) Find both the potential energy of the system when the car is at points circle a and ...
Tuesday, March 4, 2014 at 11:26pm

Physics
A 96.0-g wooden block is initially at rest on a rough horizontal surface when a 11.4-g bullet is fired horizontally into (but does not go through) it. After the impact, the block–bullet combination slides 6.5 m before coming to rest. If the coefficient of kinetic friction...
Tuesday, March 4, 2014 at 11:22pm

Physics
A sound wave in a solid has a frequency of 15.0 kHz and a wavelength of 0.333 m. What would be the wave speed, and how much faster is this speed than the speed of sound in air?
Tuesday, March 4, 2014 at 10:45pm

AP physics
Pilots of high-performance fighter planes can be subjected to large centripetal accelerations during high-speed turns. Because of these accelerations, the pilots are subjected to forces that can be much greater than their body weight, leading to an accumulation of blood in the...
Tuesday, March 4, 2014 at 10:42pm

physics
The plane is traveling at 288 m/s on a vertical circle of radius 622 m. Determine the ratio of the normal force to the magnitude of the pilot's weight. For comparison, note that black-out can occur for ratios as small as 2 if the pilot is not wearing an anti-G suit.
Tuesday, March 4, 2014 at 10:41pm

physics
A stone is tied to a string (length = 1.25 m) and whirled in a circle at the same constant speed in two different ways. First, the circle is horizontal and the string is nearly parallel to the ground. Next, the circle is vertical. In the vertical case the maximum tension in ...
Tuesday, March 4, 2014 at 10:19pm

introductory to physics
A pendulum bob is released from some initial height such that the speed of the bob at the bottom of the swing is 4.0 m/s. The acceleration of gravity is 9.81 m/s 2 . What is the initial height of the bob? Answer in units of m
Tuesday, March 4, 2014 at 10:10pm

physics
A bullet with mass 4.95 g is fired horizontally into a 1.994 kg block attached to a horizontal spring. The spring has a constant 5.58 10^2 N/m and reaches a maximum compression of 6.27 cm. (a) Find the initial speed of the bullet-block system. (b) Find the speed of the bullet.
Tuesday, March 4, 2014 at 10:06pm

physics
Can you help me everybodyyyy!!!! A charge Q = 14.0 μC is distributed evenly on a wire bent into an arc of radius R = 40.0 cm, as shown in the figure. What is the electric field at the center of the arc that subtends θ = ±53.0°?
Tuesday, March 4, 2014 at 10:01pm

physics
A pilot heads her plane with a velocity of 275 km/hr north. If there is a strong wind of 130 km/hr blowing east, what is the magnitude of the velocity of the plane in reference to the ground.
Tuesday, March 4, 2014 at 10:01pm

physics
dabuifs
Tuesday, March 4, 2014 at 9:56pm

Physics
Does it take twice the work to stretch a spring 2cm from its equilibrium position as it does to stretch it 1cm from its equilibrium position? Yes it does. (Just want to double check my answer)
Tuesday, March 4, 2014 at 9:47pm

Physics
a. Range = Vo^2*sin(2A)/g = 60 m. Vo^2*sin(60)/9.8 = 60 0.0884Vo^2 = 60 Vo^2 = 679 Vo = 26.06 m/s.[30o] b. Yo = 26.06*sin30 = 13.03 m/s = Ver. component. hmax = (Y^2-Yo^2)/2g hmax = (0-13.03^2)/-19.6 = 8.66 m.
Tuesday, March 4, 2014 at 9:23pm

Physics
NONE !!!! work is force IN THE DIRECTION OF MOTION times distance
Tuesday, March 4, 2014 at 9:20pm

Physics
You are carrying a backpack across campus. What is the work done by your verticals carrying force on the backpack? Please explain...
Tuesday, March 4, 2014 at 9:17pm

Physics
A 96.0-g wooden block is initially at rest on a rough horizontal surface when a 11.4-g bullet is fired horizontally into (but does not go through) it. After the impact, the block–bullet combination slides 6.5 m before coming to rest. If the coefficient of kinetic friction...
Tuesday, March 4, 2014 at 9:09pm

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