Friday
August 1, 2014

# Homework Help: Science: Physics

Physics
A stone is thrown in the air with an initial velocity of 50 m/s at 37 degrees to the horizontal. Find the total time the ball is in the air. What would be the total distance traveled?
Sunday, March 23, 2014 at 5:53pm

Physics
A stone is thrown in the air with an initial velocity of 50 m/s at 37 degrees to the horizontal. Find the total time the ball is in the air.
Sunday, March 23, 2014 at 4:22pm

physics
A light bulb is placed 16.6 cm in front of a concave mirror. When the concave mirror is replaced by a plane mirror in the same location, the bulb's image moves 5.40 cm closer to the mirror. Calculate the focal length of the concave mirror. i know that for plane mirrors ...
Sunday, March 23, 2014 at 3:00pm

Physics
if you throw a 0.2 kg ball straight up at 8 m/s how high will it go
Sunday, March 23, 2014 at 2:14pm

Physics
explain the input energy and out put energies of two kitchen machines
Sunday, March 23, 2014 at 2:12pm

Physics
consider a toy car that you pullback to make it go forward. Is it a force multiplier or a distance multiplier? Defend your answer with the observations you could make
Sunday, March 23, 2014 at 2:11pm

physics
a bus starts from rest and achieves a velocity of 20m/s in 10s while moving westwards.calculate its avarage acceleration
Sunday, March 23, 2014 at 11:31am

physics
A particle moves along a straight line such that its position is defined by s = (t3 – 3 t2 + 2 ) m. Determine the velocity of the particle when t = 4 s.
Sunday, March 23, 2014 at 9:43am

physics
Hydraulic engineers in the United States often use, as a units of volume of water, the acre-foot, defined as the volume of water that will cover 1 acre (where 1 acre = 43560 ft2) of land to a depth of 1 ft. A severe thunderstorm dumped 2.6 in. of rain in 30 min on a town of ...
Sunday, March 23, 2014 at 8:02am

physics
The micrometer (1 μm) is often called the micron. (a) How many microns make up 1.5 km? (b) How many centimeters equal 1.5 μm? (c) How many microns are in 1.5 yd?
Sunday, March 23, 2014 at 8:00am

physics
A gry is an old English measure for length, defined as 1/10 of a line, where line is another old English measure for length, defined as 1/12 inch. A common measure for length in the publishing business is a point, defined as 1/72 inch. What is an area of 0.42 gry2 in points ...
Sunday, March 23, 2014 at 7:58am

physics
Earth is approximately a sphere of radius 6.37 × 106 m. What are (a) its circumference, (b) its surface area, and (c) its volume? please help
Sunday, March 23, 2014 at 7:57am

physics
if you throw a 0.2 kg ball strait up at 8 m/s how high will it go
Sunday, March 23, 2014 at 7:48am

physics
explain the input energy and out put energies of two kitchen machines
Sunday, March 23, 2014 at 7:46am

physics
What are the principles behind seatbelts and air bags that make passengers safer in a collision?
Sunday, March 23, 2014 at 7:43am

physics
consider a toy car that you pullback to make it go forward. Is it a force multiplier or a distance multiplier? Defend your answer with the observations you could make
Sunday, March 23, 2014 at 7:42am

physics
From t = 0 to t = 3 min 25 seconds, a man stands still, and from t = 3 min 25 seconds to t = 7 mins 35 s, he walks briskly in a straight line at a constant speed of 1.65 m/s. What is the magnitude of his average velocity vavg over this entire time interval?
Sunday, March 23, 2014 at 4:04am

physics
A person has a choice while trying to move a crate across a horizontal pad of concrete: push it at a downward angle of 30 degrees, or pull it at an upward angle of 30 degrees. If the crate has a mass of 50.0 kg and the coefficient of friction between it and the concrete is 0....
Sunday, March 23, 2014 at 1:04am

physics
A 2400 kg car moving at 11 m/s crashes into a tree and stops in 0.26 s. calculate the force the seat belt exerts on passenger in the car to bring him to a halt the mass of the passenger is 72 kg.
Saturday, March 22, 2014 at 3:35pm

PHYSICS
A plane flying horizontally at 180 m/s drops a box just as it crosses a coastline. The box lands 3 kilometers from the coast. - At what height is the plane flying? - How long it takes to the box to reach the ground ?
Saturday, March 22, 2014 at 1:38pm

Physics
Consider two diffraction gratings. One grating has 3000 lines per cm, and the other one has 6000 lines per cm. Both gratings are illuminated with a beam of the same monochromatic light. Which grating produces the greater dispersion? Both gratings produce the same dispersion. ...
Saturday, March 22, 2014 at 12:46pm

Physics
A single-slit diffraction pattern is formed on a distant screen. If the width of the single slit through which light passes is reduced, what happens to the width of the central bright fringe? Assume the angles involved remain small. The central bright fringe becomes wider. The...
Saturday, March 22, 2014 at 12:46pm

college physics 2
A double-slit diffraction pattern is formed on a distant screen. If the separation between the slits decreases, what happens to the distance between interference fringes? Assume the angles involved remain small. A double-slit diffraction pattern is formed on a distant screen. ...
Saturday, March 22, 2014 at 12:45pm

physics
In a double-slit experiment, two beams of coherent light traveling different paths arrive on a screen some distance away. What is the path difference between the two waves corresponding to the third bright band out from the central bright band? The path difference between the ...
Saturday, March 22, 2014 at 12:44pm

Urgent Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Saturday, March 22, 2014 at 6:42am

physics/calc
An anchor weighing 110 lb in water is attached to a chain weighing 2 lb/ft in water. Find the work done to haul the anchor and chain to the surface of the water from a depth of 35 ft.
Friday, March 21, 2014 at 11:14pm

Physics
You pull a sled across a horizontal frictionless patch of snow. If your pulling force is in the same direction as the sled's displacement and increases the kinetic energy of the sled by 34%, by what percentage would the sled's kinetic energy increase if the pulling ...
Friday, March 21, 2014 at 10:19pm

physics
Three identical uniform meter sticks are placed on the floor. The first stick lies along the y axis from y = 0.320 m to y = 1.32 m. The second stick lies along the x axis from x = 0.330 m to x = 1.33 m. The third stick is positioned so that one end is on the x axis at x = 0....
Friday, March 21, 2014 at 10:01pm

physics
A solid block of mass m2 = 1.0 $kg$, at rest on a horizontal frictionless surface, is connected to a relaxed spring (with spring constant k = 260 N/m whose other end is fixed. Another solid block of mass m1 = 2.4 kg and speed v1 = 3.3 m/s collides with the 1.00 kg block. If ...
Friday, March 21, 2014 at 9:54pm

Physics
A 300 kg piano slides 4.4 m down a 30° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40.(a) Calculate the magnitude of the force exerted by the man.(b) Calculate the work...
Friday, March 21, 2014 at 9:17pm

Physics
What is the minimum work needed to push a 1075 kg car 230 m up along a 17.5° incline? (a) Ignore friction. (b) Assume the effective coefficient of friction retarding the car is 0.30?
Friday, March 21, 2014 at 9:06pm

Physics
A 300 kg piano slides 4.4 m down a 30° incline and is kept from accelerating by a man who is pushing back on it parallel to the incline. The effective coefficient of kinetic friction is 0.40. (a) Calculate the magnitude of the force exerted by the man. (b) Calculate the ...
Friday, March 21, 2014 at 9:05pm

physics
A person has a choice while trying to move a crate across a horizontal pad of concrete: push it at a downward angle of 30 degrees, or pull it at an upward angle of 30 degrees. If the crate has a mass of 50.0 kg and the coefficient of friction between it and the concrete is 0....
Friday, March 21, 2014 at 8:55pm

physics
Block A, with a mass of 50 kg, rests on a horizontal table top. The coefficient of static friction is 0.40. A horizontal string is attached to A and passes over a massless, ideal pulley as shown. What is the smallest mass of Block B that will start A moving when it is attached...
Friday, March 21, 2014 at 8:08pm

Physics
A ball is traveling down a straight track at 20 m/s. How fast will the ball's speed be after it climbs a hill in the track that is 15 m high?
Friday, March 21, 2014 at 4:43pm

Physics
A bullet is fired into a block of wood with speed 250 m/s. The block is attached to a spring that has a spring of 200 N/m. The block embedded bullet compresses the spring a distance of 30.0 cm to the right. Determine the mass of the wooden block
Friday, March 21, 2014 at 4:07pm

physics
explain why a flat sheet of paper and a sheet of paper crumpled into a ball which are dropped from a height of 2 meters will not accelerate at the same rate?
Friday, March 21, 2014 at 3:36pm

Physics
Help please A 200.0 g copper block absorbs 2.34 × 10^3 J of heat to raise its temperature by 30.0 K. What is the specific heat of copper?
Friday, March 21, 2014 at 3:33pm

physics
If a motorboat travels 25km/h towards the sea, down a river whose velocity is 4km/h what is the boats velocity related to the shore? A, 21 km/h B, 29km/h C, 25 km/h D, 4 km/h
Friday, March 21, 2014 at 2:56pm

Physics
A train is moving at a speed of 30 m/s toward a stationary observer at a train station. The train whistle blows with an actual frequency of 336 Hz. What horn frequency is heard by the engineer (riding on the train)?
Friday, March 21, 2014 at 12:19pm

physics
Explain why voltage is constant when connecting resistance
Friday, March 21, 2014 at 7:23am

Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Friday, March 21, 2014 at 6:31am

Chemistry
The Heisenberg Uncertainty Principle: A student is examining a bacterium under the microscope. The E. coli bacterial cell has a mass of mm = 0.100fg\rm fg (where a femtogram, fg\rm fg, is 10−15g\rm 10^{-15}\; g) and is swimming at a velocity of vv = 7.00ìm/s\mu m/...
Friday, March 21, 2014 at 6:31am

physics
An advertisement claims that a particular automobile can "stop on a dime". What net force would actually be necessary to stop an automobile of mass 850kg traveling initially at a speed of 56.0km/h in a distance equal to the diameter of a dime, which is 1.8cm ?
Friday, March 21, 2014 at 5:06am

physics
if an airplane is traveling at 550 km/h into a head wind with a velocity of 40km/h what is the airplanes velocity relative to the ground
Friday, March 21, 2014 at 4:55am

Physics
If a motorboat travels 25km/h towards the sea, down a river whose velocity is 4km/h what is the boats velocity related to the shore?
Friday, March 21, 2014 at 4:31am

Physics
A Green light wave is traveling a rate of 3*10^8 m/s and a wavelength of 561 m. How fast would a red wave with a wavelength of 447m travel?
Thursday, March 20, 2014 at 10:16pm

Physics
An electromagnetic wave has a frequency of 2.04 x 10^12 Hz, What is the wavelength of this EM wave?
Thursday, March 20, 2014 at 9:51pm

Language arts help!!
1–6, read the play excerpt below and answer the questions that follow. Jaws of the Water ACT TWO At rise we see DAD, TINA, and MARK rushing in and out of the living room. Each enters carrying important items—such as sleeping bags, rain gear, and gallons of water—...
Thursday, March 20, 2014 at 8:20pm

Physics
I don't understand this question... What is the change in entropy for a system that has 250 J of heat added to it at 25°C? (Points : 1) 10 J/K 0.84 J/K 0.84 J/K 10 J/K
Thursday, March 20, 2014 at 7:32pm

Physics
A 4700 kg vehicle on a level surface experiences a force applied due to the engine of 3700 N forward. If the force of friction acting on the vehicle is 189 N backward: Determine the values of the other forces acting on the vehicle. Draw a free body diagram and determine the ...
Thursday, March 20, 2014 at 6:53pm

Physics
How much heat is required to completely boil away 0.200 kg of water (Hv = 2.26 × 10^3 kJ/kg)? (Points : 1) 4.52 × 102 kJ 2.26 × 103 kJ 4.52 × 103 kJ 1.13 × 104 kJ
Thursday, March 20, 2014 at 6:45pm

physics
Bob is pulling a 30kg filing cabinet with a force of 200N , but the filing cabinet refuses to move. The coefficient of static friction between the filing cabinet and the floor is 0.80.What is the magnitude of the friction force on the filing cabinet? Express your answer to two...
Thursday, March 20, 2014 at 6:31pm

physics
If the electron experiences a force of 5.6 x 10-6 N, how large is the field between the deflection plates?
Thursday, March 20, 2014 at 6:03pm

Physics
Two boxes of mass 7.40 and 7.00 kg are in contact and are accelerated across a horizontal surface by an force of 51.49 N applied parallel to the surface and pushing on the lighter box. The magnitude of the frictional force between the surface and the lighter mass is 9.26 N and...
Thursday, March 20, 2014 at 5:32pm

Physics
A box of sand (initially at rest) is pulled along a horizontal floor by a cable with a breaking strength of 1090.0 N. The coefficient of static friction between the box and the ground is 0.28. What should the angle between the cable and the floor be in order to move the ...
Thursday, March 20, 2014 at 5:29pm

Physics
Two blocks of weights 77.0 and 114.0 N are connected by as massless string and slide down an inclined plane making an angle of 45.0 deg. to the horizontal. The cofficient of kinetic friction between the lighter block and the plane is 0.15 and that between the heavier block and...
Thursday, March 20, 2014 at 5:23pm

physics
Explain why voltage doesn't change when connecting resistance in series
Thursday, March 20, 2014 at 5:22pm

physics
Explain why voltage is constant when connecting resistance in series
Thursday, March 20, 2014 at 5:21pm

physics
A box of mass 5.0 kg starting from rest slides down a 1.8 m long ramp inclined at an angle of 22.0 deg. from the horizontal. If the ramp is frictionless, how long will it take the box, starting from rest, to reach the bottom of the ramp? if the frictionless ramp is replaced ...
Thursday, March 20, 2014 at 5:16pm

Physics
A 115.0 kg box is pushed by a horizontal force F at constant speed up a frictionless ramp which makes an angle of 46.0 deg with the horizontal. Find the magnitude of the applied force F. what is the magnitude of the normal force between the ramp and the box?
Thursday, March 20, 2014 at 5:06pm

physics
I once was given a metal whiskey flask for being in my cousin’s wedding. When it got dented, I put in 1 gram of H2O (initially 21°C, just like the air filling the rest of the flask) and heated it up to boil the water. It popped the dent out. Assume the flask had a ...
Thursday, March 20, 2014 at 4:13pm

Physics
A 60 W light bulb at 120 V is left on in your house to prevent burglary, and the power charges 10 cents per kilowatt-hour, how much will it cost to leave the bulb on for 30 days? Please show how to work this
Thursday, March 20, 2014 at 2:45pm

Physics
An ice puck of mass m revolves on an icy surface in a circle at speed v at the end of a horizontal string of length L. The tension in the string is T Find the mass of the puck when the length of the string is 2.2m , string tension is 5.0N , and the tangential speed of the puck...
Thursday, March 20, 2014 at 2:33pm

Physics
An ice puck of mass m revolves on an icy surface in a circle at speed v at the end of a horizontal string of length L. The tension in the string is T Write the equation for centripetal force, and substitute the values T and L appropriately. Then with a bit of elementary ...
Thursday, March 20, 2014 at 2:32pm

Physics
The diameter of the base of a tapered drinking cup is 6.6cm . The diameter of its mouth is 9.8cm . The path of the cup curves when you roll it on the top of a table. How much faster does the mouth move than the base? Express your answer using two significant figures.
Thursday, March 20, 2014 at 2:27pm

Physics
Calculate the tension in a horizontal string that whirls a 1.9-kg toy in a circle of radius 2.3m when it moves at 2.8m/s on an icy surface. Express your answer to two significant figures and include the appropriate units. 1.9(2.8)^2 .. then divid by 2.3 I got 12.30 N , is this...
Thursday, March 20, 2014 at 2:25pm

Physics
In a lightning bolt, a large amount of charge flows during a time of 2.2 10-3 s. Assume that the bolt can be treated as a long, straight line of current. At a perpendicular distance of 28 m from the bolt, a magnetic field of 7.3 10-5 T is measured. How much charge has flowed ...
Thursday, March 20, 2014 at 1:56pm

Physics
Why is using mirrors to generate electricity not a common practice?
Thursday, March 20, 2014 at 1:41pm

Physics
During a tennis serve, the ball goes from rest to approximately 32.1 m/s. The average power generated during the serve is equal to 2614 Watts. If the acceleration is constant during the serve, what is the magnitude of the force acting on the ball?(? N)
Thursday, March 20, 2014 at 1:31pm

Physics
A solenoid is formed by winding 25.3 m of insulated silver wire around a hollow cylinder. The turns are wound as closely as possible without overlapping, and the insulating coat on the wire is negligibly thin. When the solenoid is connected to an ideal (no internal resistance...
Thursday, March 20, 2014 at 1:20pm

Physics
When two resistors are connected in series across a 12-V battery, 1.1A flows. When they are connected in parallel across the same battery, 6.3A flows. What is the smaller resistor's value?
Thursday, March 20, 2014 at 1:06pm

Physics
A 10-ohm resistor is attached to a 20-ohm resistor in series. This combination is then attached to a 30-ohm resistor in parallel. This is then connected to a 120-V battery. What is the current drawn from the battery?
Thursday, March 20, 2014 at 1:05pm

Physics
A direct current power supply is connected to a circuit containing one resistor, and 1.5 A is drawn. If a second identical resistor is connected to the power supply in parallel with the first, how much current is drawn from the battery?
Thursday, March 20, 2014 at 1:01pm

physics
two vectors A and B each have magnitude 220 and angle BETWEEN THEM IS 120 WHAT WILL BE RESULTANT?
Thursday, March 20, 2014 at 12:28pm

Physics
Ten cars at an intersection are blowing their horns simultaneously, creating a 98 decibel sound in the middle of the intersection. What is the average sound level for each car?
Thursday, March 20, 2014 at 11:06am

Physics
A train blows its horn as it approaches a crossing. The train engineer observes a frequency of 118 Hz and a stationary observer observes a frequency of 122 Hz. What is the speed of the train? Use the speed of sound as 340m/sec
Thursday, March 20, 2014 at 10:34am

Physics
If a piano tuner hears 3 beats each second when listening to a 8 Hz tuning fork and a single string on the piano which is of higher frequency.. What is the frequency of the single string from the piano?
Thursday, March 20, 2014 at 10:33am

physics
What is the momentum of the 200 g cart BEFORE the collision (LEAVE OUT units of kgm/s)? please help.
Thursday, March 20, 2014 at 9:31am

physics
if the cart in the last question collides INELASTICALLY with a stationary cart of mass 150 g, what is the kinetic energy of the carts after the collision (LEAVE OUT units of J)?
Thursday, March 20, 2014 at 9:29am

physics
If a cart is initially travelling at 3.5 m/s, and has a mass of 200g, what is it's kinetic energy (LEAVE OUT units of J)?
Thursday, March 20, 2014 at 9:27am

physics
If the speed of the cart at the first photogate is 2.3 m/s, and the speed of the cart at the first photogate is 1.8 m/s, what is the percentage change in the speed of the cart (LEAVE OUT the % symbol)?
Thursday, March 20, 2014 at 9:25am

physics
If the average time from one on state to the next one on the first photogate is 0.005 seconds, what is the speed of the cart at this point (LEAVE OUT the units of m/s)?
Thursday, March 20, 2014 at 9:19am

Physics
During a tennis serve, the ball goes from rest to approximately 32.1 m/s. The average power generated during the serve is equal to 2614 Watts. If the acceleration is constant during the serve, what is the magnitude of the force acting on the ball?(? N)
Thursday, March 20, 2014 at 8:23am

Physics
If you have three waves corresponding to to the lowest three frequencies of vibrations of a 30 cm air column, what is the wavelength of the standing wave in each case? What frequency is heard in each pipe? The only information I have is that the speed of sound in air is 331 m/s
Thursday, March 20, 2014 at 6:02am

Physics
A Plane flies north at 215 km/h. A wind from the east blows at 69km/h. What is the plane's new velocity with respect to the ground in standard position
Wednesday, March 19, 2014 at 11:02pm

Physics
During a tennis serve, the ball goes from rest to approximately 32.1 m/s. The average power generated during the serve is equal to 2614 Watts. If the acceleration is constant during the serve, what is the magnitude of the force acting on the ball?(? N)
Wednesday, March 19, 2014 at 10:18pm

physics
A force in the +x-direction with magnitude F(x)=18.0N−(0.530N/m)x is applied to a 7.60kg box that is sitting on the horizontal, frictionless surface of a frozen lake. F(x) is the only horizontal force on the box. If the box is initially at rest at x=0, what is its speed ...
Wednesday, March 19, 2014 at 9:35pm

Physics
Calculate the force of friction that keeps a 80-kg person sitting on the edge of a horizontal rotating platform when the person sits 2.4m from the center of the platform and has a tangential speed of 3.2m/s . Express your answer to two significant figures and include the ...
Wednesday, March 19, 2014 at 8:51pm

Physics.
Calculate the tension in a horizontal string that whirls a 1.9-kg toy in a circle of radius 2.3m when it moves at 2.8m/s on an icy surface. Express your answer to two significant figures and include the appropriate units
Wednesday, March 19, 2014 at 8:50pm

Physics
A 3.9 kg cat falls out a window. Just before landing, the cat's momentum is equal to 55.8 kg m/s. How high was the window where the cat fell from?(?m)
Wednesday, March 19, 2014 at 8:30pm

Physics!
Consider someone in a rotating space habitat. The outward force felt by the person A.has no reaction counterpart B.is an interaction with Earth C.is a form of gravity D.is real in the traditional sense
Wednesday, March 19, 2014 at 8:07pm

physics
what is the magnetic flux of a magnetic field of 3.5 x 10 T lassing a given circular surface with radius 30 cm
Wednesday, March 19, 2014 at 8:01pm

Physics
I once was given a metal whiskey flask for being in my cousin’s wedding. When it got dented, I put in 1 gram of H2O (initially 21°C, just like the air filling the rest of the flask) and heated it up to boil the water. It popped the dent out. Assume the flask had a ...
Wednesday, March 19, 2014 at 8:00pm

Physics
A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision? Answer a. 0.394 kg·m/s b. 0.632 kg&...
Wednesday, March 19, 2014 at 5:48pm

Physics
A 5.00-g bullet is fired into a 500-g block of wood suspended as a ballistic pendulum. the combined mass swings up to a height of 8.00 cm. What was the magnitude of the momentum of the combined mass immediately after the collision?
Wednesday, March 19, 2014 at 5:47pm

Physics
A 11 kg box slides 4.2 m down a frictionless ramp and then collides with a spring whose spring constant is 250 N/m. What is the maximum compression of the spring? I got 1.35 m but it is incorrect. Any help would be great!
Wednesday, March 19, 2014 at 3:51pm

Algebra Based Physics
A 2.50-kg steel ball strikes a massive wall at 10.0 m/s at an angle of θ = 60.0° with the plane of the wall. It bounces off the wall with the same speed and angle (see the figure below). If the ball is in contact with the wall for 0.224 s, what is the average force ...
Wednesday, March 19, 2014 at 2:28pm

Physics
Bats chirp at a high frequency which humans cannot hear. They use the echoes to detect small objects, such as insects, as small as one wavelength. If a bat were to emit a chirp at a frequency of 60.0 kHz and the speed of sound waves in the air are 340 m.s, what is the size in ...
Wednesday, March 19, 2014 at 2:15pm

physics question for damon (a clarification)
Hi Damon! You helped me out in this question yesterday (jiskha. com /display.cgi?id = 1395185605) and I was wondering why you added gravity when calculating the friction. Thanks for your help!
Wednesday, March 19, 2014 at 1:55pm

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