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July 23, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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Physics
Two particles with the same mass and same initial speed collide and stick together and leave the collision with half of their initial speed, bound together as one particle. What was the angle between the initial momenta of the particles before the collision?
Tuesday, May 27, 2014 at 5:58pm

Physics
A 69.5kg football player is gliding across very smooth ice at 2.15m/s . He throws a 0.470kg football straight forward. What is the player's speed afterward if the ball is thrown at 16.0m/s relative to the ground? What is the player's speed afterward if the ball is ...
Tuesday, May 27, 2014 at 5:37pm

Physics
A 275-gram ball bounces off a wall. The ball stays in a horizontal plane throughout the motion. The ball strikes the wall with a speed of 4.50 m/s at an angle of 𝜃 = 35.0o relative to the wall and rebounds with the same speed at the same angle. If the ball is in ...
Tuesday, May 27, 2014 at 5:21pm

physics
Find the required angular speed, ω, of an ultracentrifuge for the radial acceleration of a point 2.00cm from the axis to equal 6.00×105 g (where g is the acceleration due to gravity).
Tuesday, May 27, 2014 at 5:10pm

Physics, am i right?
A 10.0 Ω resistor is in parallel with a 20.0 Ω resistor and supplied by a 9.0 V battery. What is the current passing through the 20.0 Ω resistor? (Points : 1) 0.45 A 0.90 A 1.35 A <--- 6.00 A
Tuesday, May 27, 2014 at 4:44pm

Physics
I'm confused with this one, here's what i got 45.0 v/ 40.0Ω = 1.125 A is the answer b? A 10.0 Ω resistor is in parallel with a 30.0 Ω resistor and supplied by a 45.0 V battery. What is the total current drawn from the battery? 0.003 A 1.10 A 6.00 A 338 A
Tuesday, May 27, 2014 at 4:30pm

Physics
Two particles with the same mass and same initial speed collide and stick together and leave the collision with half of their initial speed, bound together as one particle. What was the angle between the initial momenta of the particles before the collision?
Tuesday, May 27, 2014 at 3:07pm

physics
What is the maximum walking speed of an adult man whose legs are each 0.90 m long?
Tuesday, May 27, 2014 at 2:51pm

Physics
Help me with this please When a 20 V battery is hooked up to a 10 Ω resistor in a circuit, how much current flows through the circuit? 0.5 A 2 A 20 A 200 A
Tuesday, May 27, 2014 at 2:32pm

physics-force and pressure
find pressure when force is 300N and area is 700cm^2
Tuesday, May 27, 2014 at 12:53pm

physics
What force exists between a positive charge of 2.6 x 10-6 C and a negative charge of 4.2 x 10-5 C if they are separated by 8 cm?
Tuesday, May 27, 2014 at 8:24am

Physics 2
four equal-magnitude (4uc)charges are placed at the four corners of a square that is 20cm on each side.find the electric field intensity at the center of square , if the charge are all positive.
Tuesday, May 27, 2014 at 7:50am

Physics
an electron is sitting 10cm away from a small object -5nc it is let go and moves away from the charged object when it reaches a distance of 15 cm away find its speed
Monday, May 26, 2014 at 6:27pm

Physics
Please help me! 1)1. Two charged point bodies are placed into the opposite on diagonal vertices of a rectangular with sides of 6 and 8 cm in vacuum – Q1=3.2x10-11 C; Q2=-4.267x10-11 C. Calculate the electric field intensity at two other vertices of the rectangular and the...
Monday, May 26, 2014 at 6:04pm

physics
How much heat is added to 10.5 g of ice at -20.0°C to convert it to steam at 123.5°C?
Monday, May 26, 2014 at 4:33pm

physics
A force 457 Newtons causes a displacement 6.2 metres which is at an angle of 8 degrees to the direction of the force vector. Calculate the work done by the force.
Monday, May 26, 2014 at 1:49pm

physics
A student of mass 64.7 kg climbs up the stairs in the Physics Department, with a vertical height change 3.1 metres. What is the change in gravitational potential energy? Give your answer in Joules, to 2 significant figures.
Monday, May 26, 2014 at 1:48pm

physics
What work is done by a friction force acting on an object? Select one: a. Always negative b. Always positive c. May be positive or negative depending on the choice of coordinate system d. Always zero
Monday, May 26, 2014 at 1:47pm

physics
An electron of charge -e and a long straight wire carrying a current I to the right are both in the plane of the page, as shown above. In the position shown, the electron is a distance R from the wire and is moving directly toward it with speed v. What is the direction of the ...
Monday, May 26, 2014 at 12:38pm

physics
12 wires each of resistance 'r' ohm are connected to form a cube. Find the resistance if current enters through one edge and leaves through other corner of the same edge of the cube
Monday, May 26, 2014 at 2:28am

physics
You push your backpack, mass 2.8 kg across the desk with a force of 49.3 N. Calculate the acceleration of the backpack. Neglect friction forces and give your answer to 3 significant figures.
Monday, May 26, 2014 at 1:12am

physics
What is the frequency of the second hand of a clock, assuming it is keeping correct time? Select one: a. 1 Hz b. π/3 Hz c. 0.0167 Hz d. 60 Hz
Monday, May 26, 2014 at 1:11am

physics
A force 457 Newtons causes a displacement 6.2 metres which is at an angle of 8o to the direction of the force vector. Calculate the work done by the force.
Monday, May 26, 2014 at 1:08am

college physics
A student of mass 64.7 kg climbs up the stairs in the Physics Department, with a vertical height change 3.1 metres. What is the change in gravitational potential energy? Give your answer in Joules, to 2 significant figures.
Monday, May 26, 2014 at 1:06am

college physics
What work is done by a friction force acting on an object? Select one: a. Always negative b. Always positive c. May be positive or negative depending on the choice of coordinate system d. Always zero
Monday, May 26, 2014 at 1:03am

Physics
A golf ball is struck by a golf club at 55 m/s at an angle of 28.0o above the horizontal. The mass of the ball is 45 grams and is in contact with the golf club for 1.5 m/s. Calculate the average force exerted on the ball by the club.
Monday, May 26, 2014 at 1:03am

Physics
Two particles with the same mass and same initial speed collide and stick together and leave the collision with half of their initial speed, bound together as one particle. What was the angle between the initial momenta of the particles before the collision?
Monday, May 26, 2014 at 1:02am

Physics
A sled of mass 9.0 kg is sliding across a frozen lake with a speed of 5.0 m/s. A package of mass 4.0 kg is dropped onto it from above. Assuming there is no friction between the sled and the lake, what is the new speed of the sled?
Monday, May 26, 2014 at 1:02am

physics
An Angry Bird sits on a clothes line midway between the two poles. bird on line If the combined weight of the bird and rope is W, what is the tension in the rope in terms of θ and W? Select one: a. W cosθ / sinθ b. W tanθ c. W/(2sinθ) d. W/(2cosθ)
Monday, May 26, 2014 at 12:54am

physics
An aircraft has an initial mass of m0 and an initial acceleration of a0. After flying for 2 hours, the mass of the aircraft has decreased by 11%, due to the burning of the fuel. If the propulsive force provided by the engines is constant, what is the expression for the new ...
Monday, May 26, 2014 at 12:52am

Physics
A 50kg mass and a 85kg mass are hung over a frictionless pulley what is the acceleration of the system
Monday, May 26, 2014 at 12:17am

college physics
A car travels around a bend of radius R at a speed v1, experiencing a centripetal acceleration ac. The car then travels around a curve with the same radius R, but with a centripetal acceleration which has twice the magnitude of ac. What speed is the car moving, when going ...
Sunday, May 25, 2014 at 6:43pm

physics
You drop a ball, mass 127.5 grams from a height of 83.0 cm. It bounces back to a height of 50.5 from the floor. What is the change in gravitational potential energy from the moment it is dropped, to the moment it reaches the maximum height from the bounce?
Sunday, May 25, 2014 at 6:37pm

physics
You are in the supermarket, pushing a cart with a force of 79 Newtons in the horizontal direction. There is a constant force of kinetic friction operating on the cart of 14.2 Newtons. Calculate the net work done on the cart, if the cart is displaced 1.2 metres in a straight line.
Sunday, May 25, 2014 at 6:36pm

physics
You throw a ball with a mass of 182.2 g, with a speed of 4.6 m/s. Calculate the kinetic energy in Joules to 3 s.f. , and what is the uncertainty C=1 (Unsure: <67%) C=2 (Mid: >67%) C=3 (Quite sure: >80%)?
Sunday, May 25, 2014 at 6:25pm

Physics
(637) A cyclist is riding on a horizontal frozen meadow. He is turning so that he is tilted at an angle of 60°. Radius of curvature of the bend is 100m. What is the maximum speed of the cyclist? Thank you for your time!
Sunday, May 25, 2014 at 11:43am

physics
An athlete stretches a spring an extra 15.9 cm beyond its initial length. How much energy has he transferred to the spring
Sunday, May 25, 2014 at 9:42am

Physics
(595)Vinyl record spinning at 45rpm. What is the frequency of rotation (in Hz)? What is the orbital time of the vinyl record (in seconds)?
Sunday, May 25, 2014 at 3:36am

Physics
A car B travellin at constant velocity of 25m/s overtakes a stationary car B.Two seconds later,carB sets off in pursuit accelerating at a uniform 6m/s^2.How far does B travel before catching up with carA?
Sunday, May 25, 2014 at 12:38am

PHYSICS
two forces of magnitude 8N making an angle of 30 and 120 with xaxis . the y component of resultant A/ O B/ 4N C/ 8N D/ 16N
Saturday, May 24, 2014 at 12:53pm

physics
A jet plane is flying horizontally with a speed of 500 m/s over a hill that slopes upward with a 3% grade (i.e., the "rise" is 3% of the "run"). What is the component of the plane's velocity perpendicular to the ground? (Assume the +x-direction is up ...
Saturday, May 24, 2014 at 11:45am

physics
A 65.0-kg circus performer is fired from a cannon that is elevated at an angle of 55.8 ¡ã above the horizontal. The cannon uses strong elastic bands to propel the performer, much in the same way that a slingshot fires a stone. Setting up for this stunt involves ...
Saturday, May 24, 2014 at 11:39am

Math
Kelly's scores on the first three tests in her physics class are 79, 84, and 68. Determine all scores on the fourth test that will yield an average test score of at least 80.
Saturday, May 24, 2014 at 1:40am

physics
the density of a cube is measured by it's mass and length of it's side if the maximum error in the measurement of mass and length are 3% and 2% respectively. the maximum error in the measurement of density of cube is?
Saturday, May 24, 2014 at 1:38am

physics
Gamma rays (ã-rays) are high-energy photons. In a certain nuclear reaction, a ã-ray of energy 0.510 MeV (million electronvolts) is produced. Compute the frequency of such a photon.
Saturday, May 24, 2014 at 12:52am

physics
two forces of magnitude 8N making an angle of 30 and 120 with +xaxis . FInd the y component of reultant
Saturday, May 24, 2014 at 12:31am

Physics
Am i correct? Which of the following is a reasonable power rating on an electric oven? 220 V 8.0 A <-- this one seems reasonable 10.0 kW 50.0 kW-h
Friday, May 23, 2014 at 8:54pm

Physics
am i correct? A stream of moving charges results in a current of 5.6 A. How long does 116 C of charge take to flow past a fixed point? 2.0 s 5.6 s 11.2 s 21 s <--- i believe its D, because 116 C/5.6 A = 20.7 s
Friday, May 23, 2014 at 8:42pm

Physics
Help needed Which of the following is equivalent to one ampere? 10 s/10 C 10 C/10 m 1.5 C/1.5 s 15 C/10 s
Friday, May 23, 2014 at 8:35pm

physics
A subcompact car, mass 1,000 kg, runs into and sticks to an at rest, 2,200 kg SUV. If their final speed is 4.7m/s ,what was the smaller cars initial speed? a) 67 m/s b) 30m/s c) 2.2 m/s d) 15 m/s
Friday, May 23, 2014 at 4:04pm

physics
What is the ratio of the speed of sound in air at 0°C to the speed at 100°C?
Friday, May 23, 2014 at 9:04am

Physics
20.00 cm of space is available. How long a piece of brass at 20°C can be put there and still fit at 200°C? Brass has a linear expansion coefficient of 19 × 10^-6/C°. 19.93 cm 19.69 cm 19.50 cm 19.09 cm
Friday, May 23, 2014 at 8:48am

physics
1500 cm3 of ideal gas at STP is cooled to -20°C and put into a 1000 cm3 container. What is the final gauge pressure? 11 kPa 40 kPa 113 kPa 141 kPa 240 kPa
Friday, May 23, 2014 at 8:46am

physics
maximum and minimum magnitude of resultant of two vectors r 17 and 7 respectively what is the magnitude of resultant vector when both r perpendicular to each other??
Friday, May 23, 2014 at 3:15am

Physics questoin
A satellite has an orbital radius of 3.74x10^7 m. If it has a period of 49776 seconds, what is the mass of the planet?
Thursday, May 22, 2014 at 9:04pm

physics
An object with a charge of +2.07e-5 is placed 6.07 m away from an object with a charge of -4.64e-6. Find the magnitude of the electric force.
Thursday, May 22, 2014 at 9:02pm

physics
A new planet has been discovered which has a mass of 4.56 x 10^24 kg, and a radius of 7.09 x 10^6 m. What is the gravitational acceleration near the surface of this planet?
Thursday, May 22, 2014 at 8:59pm

physics
If you walk at 2 m/s in a perfect circle, what is changing?
Thursday, May 22, 2014 at 6:23pm

Physics
At 10:00 .hrs a 1.5- m-long vertical stick in air casts a shadow 1.4 m long. If the same stick is placed at 10:00 hrs in air in a flat bottomed pool of salt water half the height of the stick, how long is the shadow on the floor of the pool? (For this pool, n = ...
Thursday, May 22, 2014 at 6:23pm

physics
a shell of mass 0.020 kg is fired by a gun of mass 100kg.if the muzzle speed of the shell is 80m/s.what is the recoil speed of the gun
Thursday, May 22, 2014 at 6:32am

physics
a man walks 8km North and then 5km in a. direction 60degrees. find its distance from his starting point
Thursday, May 22, 2014 at 1:35am

physics
two vectors of magnitudes 7 units and 15 units can never give resultant of? a)7 units b)11 units c)13 units d)20 unit
Thursday, May 22, 2014 at 1:31am

Physics
A bird lands on a bare copper wire carrying a current of 27 A. The wire is 8 gauge, which means that its cross-sectional area is 0.13 cm2. (a) Find the difference in potential between the bird's feet, assuming they are separated by a distance of 7.2 cm.
Wednesday, May 21, 2014 at 9:38pm

physics
A car with a mass of 2,000 kg has a kinetic energy of 900,000 J. How fast is it traveling?
Wednesday, May 21, 2014 at 9:17pm

physics
At the top of a hill, a roller coaster has 67,500 J of kinetic energy and 290,000 J of potential energy. Gradually, the roller coaster comes to a stop due to friction. If the roller coaster has 30,000 J of potential energy when it stops, how much heat energy is generated by ...
Wednesday, May 21, 2014 at 9:02pm

Physics
what is the role of a commutator in a DC motor?
Wednesday, May 21, 2014 at 6:50pm

Physics -- check answers please
The earth's magnetic field a) is slightly off centre compared to the Earth's rotational axis of rotation b) has its magnetic south pole at the geographic north pole c) attracts the north end of the compass needle to the geographic north pole d) all of the above Would ...
Wednesday, May 21, 2014 at 5:09pm

Physics
2. How much energy would a body of mass 50kg need to provide for the following: a. Climbing a hill 500m high. b. Walking up steps 10m tall. c. Jumping 10cm up.
Wednesday, May 21, 2014 at 11:11am

physics
A person has a 2 resistance coils. By using them singly, in series or in parallel, he obtains 2 ohm, 4 ohm, 12 ohm, and 16 ohm. What is the new resistance?
Wednesday, May 21, 2014 at 10:41am

physics
A man stands on his balcony, 120 ft above the ground. He looks at the ground, with his sight line forming an angle of 50 degrees with the building, and sees a bus stop. The function d = 120 sec θ models the distance form the man to any object given his angle of sight &#...
Wednesday, May 21, 2014 at 10:38am

Physics Please help4
Two 1.50cm -diameter disks spaced 1.80mm apart form a parallel-plate capacitor. The electric field between the disks is 5.10×10^5 V/m I got the voltage as =918 but B. How much charge is on each disk? _________C? and C. An electron is launched from the negative plate. It ...
Wednesday, May 21, 2014 at 3:57am

Physics Please help3
A point charge with charge q1 = 3.10μC is held stationary at the origin. A second point charge with charge q2 = -4.60μC moves from the point ( 0.160m , 0) to the point ( 0.270m , 0.255m ). How much work W is done by the electric force on the moving point charge? ...
Wednesday, May 21, 2014 at 3:56am

Physics Please help2
Two small insulating spheres with radius 7.00×10^−2m are separated by a large center-to-center distance of 0.565m . One sphere is negatively charged, with net charge -2.05μC , and the other sphere is positively charged, with net charge 4.10μC . The charge...
Wednesday, May 21, 2014 at 3:54am

Physics Please help
A thin, horizontal 20cm×20cm copper plate is charged with 1.7×10^10 electrons. Consider the electrons are uniformly distributed on the surface. A. What is the strength of the electric field 0.1 mm above the center of the top surface of the plate? E=____ N/C B. What...
Wednesday, May 21, 2014 at 3:53am

physics
A uniform rod 30cm long is pivoted at it's center. A 40N weight is hung 5cm from the left end. where must the 50N weight be hung to maintain equilibrium?
Wednesday, May 21, 2014 at 3:15am

Physics
How do observations of the photoelectric effect conflict with the predictions of classical physics?
Wednesday, May 21, 2014 at 12:20am

Physics
The earth's magnetic field a) is slightly off centre compared to the Earth's rotational axis of rotation b) has its magnetic south pole at the geographic north pole c) attracts the north end of the compass needle to the geographic north pole d) all of the above 2. A ...
Tuesday, May 20, 2014 at 11:32pm

language help !
Albert Einstein, a world-famous mathematician was born in Bavaria in 1879. He acquired Swiss nationality in 1901 and he began working at the Swiss patent office the next year. Einstein was however also publishing papers in physics. He became famous for his theories of ...
Tuesday, May 20, 2014 at 10:31pm

physics
If I put the tip of a 100 foot pipe in the ocean and applied a perfect vacuum to the top, how high would the water rise in the pipe?
Tuesday, May 20, 2014 at 9:57pm

Physics
An airplane whose air speed is 600 mi/h is flying perpendicularly to jet stream whose speed relative to the Earth's surface is 100 mi/h. What is the airplane's speed relative to the Earth?
Tuesday, May 20, 2014 at 8:21pm

physics
A 3.0 L balloon at 300 K is placed in a cooler at 225 K. What is the volume of the balloon after it has been in the cooler?
Tuesday, May 20, 2014 at 8:15pm

physics
An electric stove operates on a larger 220 V line. How much power is needed to cook a pizza if 0.45 A of current is used.
Tuesday, May 20, 2014 at 8:01pm

physics
A pulley applies a force of 200 N over a distance of 15 m to raise a 530 N drum 4 meters. Calculate the work output done by the pulley.
Tuesday, May 20, 2014 at 7:42pm

physics
An electron has an initial speed of 2.95 × 105 m/s.If it undergoes an acceleration of 2.7 × 1014 m/s^2, how long will it take to reach a speed of 5.94 × 105 m/s?
Tuesday, May 20, 2014 at 7:41pm

physics
A 4.0 kg ceiling fan is placed 2.5 m above the floor. What is the gravitational potential energy of the fan(use Earth's value for gravitational acceleration)?
Tuesday, May 20, 2014 at 7:31pm

Physics
What is the mass (in Grams) of a block of aluminum that has a volume of 385 mL
Tuesday, May 20, 2014 at 7:24pm

Physics
I don't want an answer I would just like to know what equations to use to answer the questions. It's confusing me. i. imgur. com/6CouaRj .png An astronaut lands on an alien planet. He places a pendulum (L = 0.200 m) on the surface and sets it in simple harmonic motion...
Tuesday, May 20, 2014 at 6:25pm

Physics
A heat engine has a hot reservoir of 680°C and a cold reservoir of 220°C. What is the efficiency of the engine?
Tuesday, May 20, 2014 at 5:27pm

Physics
1.How are alternating and direct current different? 2.Who invented direct current? 3.Who invented alternating current? 4.What are some of the advantages of alternating current? 5.Do all devices that plug into the wall run on alternating current? Why/why not? 6.What is the ...
Tuesday, May 20, 2014 at 3:33pm

physics
A fire hose exerts a force on the person holding it. This is because the water accelerates as it goes from the hose through the nozzle. How much force is required to hold a 7.5 cm diameter hose delivering 450 L/min through a 0.80cm diameter nozzle?
Tuesday, May 20, 2014 at 9:55am

Physics
How to solve? 2. A 70.0 kg astronaut is training for accelerations that he will experience upon reentry. He is placed in a centrifuge (r = 10.0 m) and spun at a constant angular velocity of 16.3 rpm. Answer the following: a. What is the angular velocity of the centrifuge in ...
Tuesday, May 20, 2014 at 6:46am

Physics
Resolve a force of 7.5N acting at an angle 40 to its horizontal an vertical components.
Tuesday, May 20, 2014 at 5:03am

physics
what is the heat required to convert 0.1 kg of melting ice into steam at 100 degree celcius
Tuesday, May 20, 2014 at 4:58am

Physics
A small block with a mass of m = 0.120 kg is attached to a cord passing through a hole in a frictionless, horizontal surface. The block is originally revolving at a distance of 0.40 m from the hole with a speed of 0.70 m/s. The cord is pulled from below, shortening the radius ...
Tuesday, May 20, 2014 at 2:45am

Physics
A force of 800 N stretches a spring a distance 0.200 m horizontally. a) What is the potential energy of the spring when it is stretched 0.200m b) What is its potential energy when it is compressed 5.00cm This is a conservation of energy problems. The potential is elastic and ...
Tuesday, May 20, 2014 at 2:44am

Physics
Help with Physics homework Please and thank you!? I need help on these two questions. I'm not looking for the answer because I really need to learn how to do this on my own. But if someone could show me what equations to use to answer the steps in the questions and explain...
Tuesday, May 20, 2014 at 2:03am

Physics
a 40kg girl and a 30kg boy face each other on friction free roller skates. the boy pushes the girl,
Monday, May 19, 2014 at 10:51pm

Physics
Calculate the equilibrium position of a third charge of 6.79 x 10^-9 C that is positioned between an 8 x 10^-9 C charge and a 12 x 10^-9 c charge.
Monday, May 19, 2014 at 9:59pm

physics
Calculate the gravity on a planet using a pendulum that has a period of 2.45 s having a length of 1.25 m.
Monday, May 19, 2014 at 9:57pm

Physics
2.0 kg weight is on simple, horizontally oscillation (in a spring) with the time 1.8 s. The distance between the outmost dots in the oscillation is 0.16 m. a) What is the angular speed (w) of the oscillation ? b) What is the force constant (k) of the spring? c) What is the ...
Monday, May 19, 2014 at 12:19pm

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