# Posts by Physics

Total # Posts: 427

**Physics**

A 6 kg grinding wheel of radius 0.2 m rotates at a constant rotational frequency of 4 rad/s when an object makes contact with the outer edge of the wheel. Friction causes the wheel to stop in 2 seconds. What is the average torque on the wheel by the frictional force?

*February 5, 2013*

**5th grade math**

To find out how many bows Alicia can make, divide 4 yards by 1/3 and you will get the answer that Victoria provided.

*February 4, 2013*

**math6**

I presume that all you have to do is divide the amount of miles that she drove by how long she drove. 621miles/11.5hours=54miles/hour

*February 4, 2013*

**Melanie**

A right triangle has a hypotenuse of length 13 meters and one side of length 5 meters. What is the length of the third side and the angle between the hypotenuse and the 5 meter side? A. 144 meters, 67.38 degrees B. 12 meters, 22.62 degrees C. 10 meters, 22.62 degrees D. 12 ...

*January 19, 2013*

**physics**

A car with a mass of 3200 kg and a velocity of 50 m/s brakes to a final velocity of 25m/s in a distance of 85 m. what is the force the brakes apply to stop the car.

*January 15, 2013*

**physics**

A hiker, who weighs 1120 N, is strolling through the woods and crosses a small horizontal bridge. The bridge is uniform, weighs 3775 N, and rests on two concrete supports, one at each end. He stops one-fifth of the way along the bridge. What is the magnitude of the force that ...

*December 10, 2012*

**physics**

In an arcade game a 0.135 kg disk is shot across a frictionless horizontal surface by compressing it against a spring and releasing it. If the spring has a spring constant of 155 N/m and is compressed from its equilibrium position by 7 cm, ﬁnd the speed with which the ...

*November 28, 2012*

**Physics**

A basketball of mass 0.70 kg is dropped from rest from a height of 1.22 m. It rebounds to a height of 0.64 m. How much mechanical energy was lost during the collision with the floor? A basketball player dribbles the ball from a height of 1.22 m by exerting a constant downward ...

*November 27, 2012*

**physics**

Exactly 11 kJ of energy was absorbed by 1 mol of Cl2(g) at 298 K. What i s thefinal temperature of the Cl2(g)? The heat capacity of Cl2(g) is 25.635J.K-1.mol-1

*September 25, 2012*

**Taylor**

The blck mamba is one of the world's most poisonous snakes, and with a maximum speed of 18.0 km/h, it is also the fastest. Suppose a mamba waiting in a hide-out sees prey and begins slithering toward it with a velocity of +18.0 km/h. After 2.50 s, the mamba realizes that ...

*September 23, 2012*

**physics**

Boring physics

*July 20, 2012*

**Physics need work checked**

Physics lenses. Please help, my math is wrong and I need second opinion.? Consider three lenses with focal lengths of 25.9 cm, -15.8 cm, and 10.0 cm positioned on the x axis at x1 = 0 m, x2 = 0.412 m, and x3 = 0.514 m, respectively. An object is at d = -121 cm. Find the ...

*May 2, 2012*

**help**

from which equations is the following equation derived from: length=(time^2 * g)/4

*April 4, 2012*

**emily**

What is the potential halfway between two point charges spaced 1 mm apart if q1=10 micro culumbs and q2= -5 micro culumbs

*February 15, 2012*

**jane**

In an electric field described by E = (20i+60j) V/m calculate the change in potential for a particle that moves from the origin to the coordinates (3,3)m

*February 15, 2012*

**TOm**

Hello, this is the last question that I can't seem to or be able to solve: 1. Jenny (75 kg) goes on a ski trip. She goes down a slope that's inclined at 15*. The drag coefficient of Jenny is 0.300, the surface of contact with air is 0.750 m^2 and the air density is 1,...

*January 27, 2012*

**electric force/field**

Three point charges, A = 2.2 µC, B = 7.5 µC, and C = -3.9 µC, are located at the corners of an equilateral triangle . Find the magnitude and direction of the electric field at the position of the 2.2 µC charge. magnitude = . N/C direction =

*January 23, 2012*

**victor.M**

What is the resulting temperature when a 150g cube of ice at zero degrees is added to 200g of water in a aluminium cup at 30 degrees

*January 12, 2012*

**A man wants to cross a river 500 m wide which flows at speed of 2 km/hr.the man rows a boat perpendicular to the river flow at 3 km/hr relative to the river.what is relative velocity of boat relative to the ground?**

Velocity of boat relative to the river(vbr):3 km/hr, velocity of river relative to ground(vrg) :2 km/hr. Velocity of boat relative to the ground(vbg): square root of 9+4

*November 20, 2011*

**Physics 101**

The systemis in equilibrium and the pulleys are frictionless and massless. |_________________________| l l l ( . ) l / \ | / \ ( . ) 8kg | I 2kg ( . ) | / \ | I 6kg ______V____I____________________ _________________________________| Find the force T. The acceleration of ...

*November 8, 2011*

**physics101**

A uniform 7.1 m tall aluminum ladder is leaning against a frictionless vertical wall. The ladder has a weight of 272 N. The ladder slips when it makes a 57.0degrees angle with the horizontal floor. Determine the coefficient of static friction between the ladder and the floor.

*November 7, 2011*

**physics**

A boat moves through the water with two forces acting on it. One is a 2.80×10 3 N forward push by the motor, and the other is a 1.56×10 3 N resistive force due to the water. a)What is the acceleration of the 1312.6 kg boat? Answer in units of m/s^2 b)If it starts ...

*October 23, 2011*

**physics 911**

A force ~F = Fx ˆı+Fy ˆ| acts on a particle that undergoes a displacement of ~s = sx ˆı + sy ˆ| where Fx = 10 N, Fy = −1 N, sx = 5 m, and sy = 3 m. Find the work done by the force on the particle. Answer in units of J b) Find the angle ...

*October 15, 2011*

**physics**

I think it's saying only gravity is affecting the particle on the y-axis.

*September 25, 2011*

**physics**

The vertical acceleration is 9.8 m/s^2 because of gravity. So in the negative y direction.

*September 25, 2011*

**physics**

Initially (at time t = 0) a particle is moving vertically at 5.8 m/s and horizontally at 0 m/s. Its horizontal acceleration is 2.1 m/s2. At what time will the particle be traveling at 54 with respect to the horizontal? The acceleration due to gravity is 9.8 m/s2.

*September 25, 2011*

**physics**

A linear charge of nonuniform density E(x)=bx C/m, where b = 5.2 nC/m2, is distributed along the x-axis from 4.9 m to 6 m. Determine the electric potential (relative to zero at infinity) of the point y = 8.6 m on the positive y-axis.

*September 24, 2011*

**physics**

The electric potential in a certain region is V = a x2 + b x + c, where a = 15 V/m2, b = −13 V/m, and c = 67 V. 1)Determine the electric field at x = 4 m. 2)Determine the position where the electric field is zero.

*September 24, 2011*

**physics**

A linear charge of nonuniform density (x) = 5.2 x C/m, is distributed along the x-axis from 4.9 m to 6 m. Determine the electric potential (relative to zero at infinity) of the point y = 8.6 m on the positive y-axis. Answer in units of V

*September 24, 2011*

**physics**

A charge of 10.104 nC is uniformly distributed along the x-axis from −1 m to 1 m. What is the electric potential (relative to zero at infinity) of the point at 5 m on the x-axis?

*September 24, 2011*

**physics**

A place kicker must kick a football from a point 36 m (about 39 yd) from the goal, and the ball must clear the crossbar, which is 3.05 m high. When kicked, the ball leaves the ground with a speed of 24 m/s at an angle of 50 to the horizontal. The acceleration of gravity ...

*September 24, 2011*

**physics**

Particle 1 is moving on the x-axis with an acceleration of 5.55 m/s2 in the positive x-direction. Particle 2 is moving on the y-axis with an acceleration of 7.45 m/s2 in the negative y-direction. Both particles were at rest at the origin at t = 0 s. Find the speed of particle ...

*September 24, 2011*

**physics**

Initially (at time t = 0) a particle is moving vertically at 5.8 m/s and horizontally at 0 m/s. Its horizontal acceleration is 2.1 m/s2. At what time will the particle be traveling at 54 with respect to the horizontal? The acceleration due to gravity is 9.8 m/s2. Answer ...

*September 24, 2011*

**Ida**

What does duracell manufacture say about the durability of their brand

*July 24, 2011*

**physics...........**

What is the probability that the bulb is glowing for a circuit set up as: |-------------(Bulb)-----------| | | | | (Voltage) | | | | | |----(Switch-1)---(Switch-2)---|

*June 25, 2011*

**physics**

Two identical traveling waves, moving in the same direction, are out of phase by /5.0 rad. What is the amplitude of the resultant wave in terms of the common amplitude ym of the two combining waves? (Give the answer as the ratio of the total amplitude to the common amplitude.)

*May 19, 2011*

**phyiscs**

what is the derivative of velocity squared? i know that the derivative of regular velocity is acceleration, but what about velocity squared? thank you very much!

*May 19, 2011*

**physics**

if the second derivative is not uniform, then is the third derivative also not uniform? thank you!

*May 19, 2011*

**Physics**

A scaffold of mass 50kg and length 5m is supported in a horizontal position by a vertical cable at each end. A window cleaner of mass 70kg stands at a point 2m from one end. Determine the tension in the nearer cable and also the farther cable.

*May 18, 2011*

**physics**

A new type of spring is found where the spring force F is given by F=-kx + bx^2 where k=400 N/ m and b=100 N/m^2 and x is the expansion (or compression) of the spring from its equilibrium position. The spring is attached to a point mass of 1 kg sitting on a horizontal ...

*April 4, 2011*

**Physics**

A brick of mass 1.0 kg slides down an icy roof inclined at 30.0 degrees with respect to the horizontal. (a) If the brick starts from rest, how fast is it moving when it reaches the edge of the roof 2.00 m away? Ignore friction. (b) Redo part (a) if the coefficient of kinetic ...

*March 26, 2011*

**physics multiple choice**

A. Because on a fricitionless horizontal surface any finite mass will accelerate if any finite net force is applied in any direction that is not perpendicular to the said surface.

*February 2, 2011*

**physics**

Pulling up on a rope, you lift a 4.05-{\rm kg} bucket of water from a well with an acceleration of 2.20 m/s^2. What is the tension in the rope?

*January 4, 2011*

**physics**

the maximum height a typical person can jump from a crouched start is about 60cm. By how much does the gravitational potential energy increase for a 72kg person in such a jump? Where does this energy come from? I know the formula for gravitational potential energy is U=mgh. I ...

*December 7, 2010*

**11th grade**

which ons is stronger 1)A solid cylinder of 2)A hollow cylinser of iron 3) A cylinder made up of slits of iron

*November 28, 2010*

**Kristen**

Thank you for your help!

*October 27, 2010*

**Kristen**

A flywheel has a moment of inertia of 2.6 kg·m2. What is the average power needed to spin it up from rest to an angular velocity of 100 rad/s in 30 seconds?

*October 27, 2010*

**physics**

Both of the answers above are wrong answer is 24°

*October 22, 2010*

**carrol high school**

A car brakes from 60 mph to a full stop in 4 seconds. Find the accelerayion of the car during this interval

*September 8, 2010*

**science**

what is the farmula of electric field due to postive charge

*August 24, 2010*

**Physics**

Obtain the final temperature, pressure and volume of the compressed air? this is the actual question part:)

*August 3, 2010*

**Physics**

A diesel engine takes in 0.5 moles of air at 20.0C and at atmospheric pressure. It then compresses it adiabatically to one twentieth of its original volume. which means n = 0.5 T = 20 and Vfinal = V1/20 but where do I go from here? can anyone help?

*August 3, 2010*

**Physics**

(b)A coin is placed 20 cm from the axis of a rotating turntable of variable speed. This speed is gradually increased and the coin remains fixed on the turntable until a rate of 36 rpm is reached. At this point, the coin slides off. What is the coefficient of static friction ...

*July 26, 2010*

**Phyics**

A Carnot engine has 200 g of helium as its working substance and operates between two reservoirs which are at temperatures of 500C and 30C. The initial volume of the gas is 20 litres while the volume after isothermal expansion is 60 litres. For one ...

*July 21, 2010*

**physics**

The problem has 55m/s... the instructor changed numbers in the original problem and I guess he wanted to change that number to 55. I thought it was strange too at first. So for conservation of momentum, would i use mhvh=mcvc where h is for human and c is for car?

*July 21, 2010*

**physics**

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2720 N) as it rolls at 18.5 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 55.00 m/s relative to the flatcar. What is ...

*July 21, 2010*

**PHYSICS**

density=mass/volume volume-mass/density

*June 28, 2010*

**Physics**

A boxer punches a 50 Kg bag. Just as his fist hits the bag, it travels at a speed of 7 m/s. As a result of hitting the bag, his hand comes to a complete stop. Assuming that the moving part of his hand weigh 5 Kg, calculate the rebound velocity and kinetic energy of the bag.

*June 28, 2010*

**magnetic field**

A square loop with resistance R=0.001 Ohms,mass 1.0 gram, and side length 1.0 m is falling into a region of uniform magnetic field. The magnetic field has strength 1 Gauss and is pointing out of the page. The speed of the loop just before it enters the region with the uniform ...

*June 7, 2010*

**electric fields *easy**

A charged particle is at the origin of coordinates. The particle produces an electric field of 4 kN/C at the point with position vector 36 cm. At what location does the field have the value 1 kN/C? Ans: 72 cm Could someone please explain to me what equation I would use and how...

*June 5, 2010*

**PHYSICS**

A long, straight wire lies on a horizontal table and carries a current of 1.45 µA. In a vacuum, a proton moves parallel to the wire (opposite the current) with a constant speed of 3.00 104 m/s at a distance d above the wire. Determine the value of d. Ignore the magnetic ...

*May 26, 2010*

**Right Hand Rule**

Consider an electron near the Earth's equator. In which direction does it tend to deflect if its velocity is directed in each of the following directions? (a) downward: WEST (b) northward . (c) westward d) southeastward I go the first one right using the right hand rule ...

*May 21, 2010*

**Physics**

The inner conductor of a coaxial cable has a radius of 0.900 mm, and the outer conductor's inside radius is 5.00 mm. The space between the conductors is filled with polyethylene, which has a dielectric constant of 2.30 and a dielectric strength of 18E6 V/m. What is the ...

*May 13, 2010*

**PHySics**

I understand now, thank you.

*May 12, 2010*

**PHySics**

A 1.63 nF parallel-plate capacitor is charged to an initial potential difference ΔVi = 100 V and then isolated. The dielectric material between the plates is mica, with a dielectric constant of 5.00. (a) How much work is required to withdraw the mica sheet? Work = .5CV^2...

*May 12, 2010*

**PHYSICS**

awesome thanks, that's the correct answer. I was using the wrong conversion. :)

*May 12, 2010*

**PHYSICS**

A 4.00 µF capacitor is connected to a 18.0 V battery. How much energy is stored in the capacitor? This should be a relatively easy problem yet, I can't get it. Isn't it just E=.5*C*V^2

*May 12, 2010*

**Physics**

I have solved this problem.

*April 29, 2010*

**Physics**

A 0.400 kg block of wood hangs from the ceiling by a string, and a 0.0700 kg wad of putty is thrown straight upward, striking the bottom of the block with a speed of 6.40 m/s. The wad of putty sticks to the block. How high does the putty-block system rise above the original ...

*April 29, 2010*

**Physics**

A 0.409 kg block is attached to a horizontal spring that is at its equilibrium length, and whose force constant is 19.5 N/m. The block rests on a frictionless surface. A 0.0500 kg wad of putty is thrown horizontally at the block, hitting it with an initial speed of 2.32 m/s ...

*April 22, 2010*

**Physics**

A 95 kg astronaut and a 1500 kg satellite are at rest relative to the space shuttle. The astronaut pushes on the satellite, giving it a speed of 0.15 m/s directly away from the shuttle. Seven-and-a-half seconds later the astronaut comes into contact with the shuttle. What was ...

*April 22, 2010*

**Physics**

this is a repeat of the question before it.

*April 22, 2010*

**Physics**

A 0.135 kg ball is dropped from rest. If the magnitude of the ball's momentum is 0.730 kg·m/s just before it lands on the ground, from what height was it dropped?

*April 22, 2010*

**Physics**

A 0.135 kg ball is dropped from rest. If the magnitude of the ball's momentum is 0.730 kg·m/s just before it lands on the ground, from what height was it dropped?

*April 22, 2010*

**Physics**

In order to keep a leaking ship from sinking, it is necessary to pump 15.0 {\rm lb} of water each second from below deck up a height of 2.00 {\rm m} and over the side.What is the minimum horsepower motor that can be used to save the ship? What is the minimum horsepower motor ...

*April 8, 2010*

**physics**

A wire 28 cm long is parallel to a 0.36 T uniform magnetic field. The current through the wire is 4.5 A. What force acts on the wire? What equation do you use? I tried F= ILBsin(90) and that didn't work!

*March 23, 2010*

**11th grade**

A wire 28 cm long is parallel to a 0.36 T uniform magnetic field. The current through the wire is 4.5 A. What force acts on the wire? What equation do you use?

*March 23, 2010*

**Gweedo8**

a man stand on a 100 m cliff and throws a rock with speed of 40ms at 42degrees above horizontal. what time before rock hits ground. the horizontal distance the rock traveled from base of cliff.? my answer is 4.08 sec before rock hits ground 81.6 m distance traveled from base ...

*January 29, 2010*

**Paul**

Determien the mass of the Sun using the known value for the period of the Earth and its distance from the Sun. I do not remeber how to do this F = ma = Fg = GmM/r^2 Period of earth 3.16 E 7 s radius earth to moon = 1.5 E 11 m

*December 22, 2009*

**Phys sci**

ITS C

*December 8, 2009*

**9th grade**

The height of the wooden block if it were to have a GPE of 300j

*November 3, 2009*

**Physics**

I could also just do sheet of glass

*October 24, 2009*

**Physics**

How much pressure is required to crack an egg under water Is there like a table I could look at that has values for how much pressure things can withstand before cracking

*October 24, 2009*

**Physics (Please)**

I'm confused and am hoping someone could help me understand energy can neither be created nor destroyed... great... so in physics classes we can set up problems and stuff were KEo + PEo = KE + PE Energy intial equals energy final sense energy is conserved but then when ...

*October 19, 2009*

**Physics**

i was woundering if you could point in the right direction i'm looking for very easy physics topics that makes use of the law of sines or the law of cosines Thanks

*October 19, 2009*

**physics**

when an object is rotating in a circle and the only force is acting on it is friction how is force of friction vector pointing towards the circle because an object in circular motion is traveling in that direction, it's accelerating towards the center of the circle, but ...

*October 12, 2009*

**Physics**

How am I doing this problem wrong On a strange, airless planet, a ball is thrown downward from a height of 17 m. The ball initally travels at 15 m/s. If the ball hits the ground in 1 s, what is this planet's gravitational acceleration? by definition of acceleration a = (v...

*October 11, 2009*

**Physics**

Ok work... work = net force parallel to displacement lets say something was pushed up a ramp at a constant velocity and you were asked how much work was done by pushing the block well the forces parellel to the displacement is the x component of gravity friction opposing ...

*October 9, 2009*

**physics egg drop**

What is the best idea for an egg drop project. it has to survive a 5 meter drope without craking or breaking open.(grade A egg wich is a bog egg). The desinge or idea has to be able to be opened and have the egg in hand within 10 sec, so packing it into boxes over and over ...

*October 6, 2009*

**Physics**

I agree with this and see were it comes from net force = (delta p)/t so momentum is conserved when net force equals zero... net force = (delta p)/t 0 = (delta p)/t however the following is not true 0 = (delta p)/t = P - Po were p is momentum and Po is used to indicate inital ...

*October 3, 2009*

**Physics**

momentum equals = mass (velocity) yet for problems I end up using this P = m (delta v) what allows us to simply put the delta infront of the v to find the momentum?

*October 3, 2009*

**Physics**

I keep on getting the wrong answer I don't know if there is even static friciton in this problem in the begining before the rope snaps or not and if so if it must be equal to the Mu they give because there is only one but you can't have the same values for both ...

*September 25, 2009*

**Physics**

I keep on getting the wrong answer I don't know if there is even static friciton in this problem in the begining before the rope snaps or not and if so if it must be equal to the Mu they give because there is only one but you can't have the same values for both ...

*September 25, 2009*

**Physics**

I'm not sure how to do this problem A .40 kg ball is thrown with a speed of 10 s^-1 m at an angle of 30 degrees. (a) What is its speed at its highest point, and (b) how high doe it go? (Use conservation of energy.)

*September 24, 2009*

**Physics**

I'm not sure how to do this problem A 145-g baseball is droppexc from a tree 12.0 m above the ground. (a) Wtih what speed would it hit the ground if air resistance could be ignored? (b) If it actually hits the ground with a speed of 8.00 s^-1 m, what is the average force ...

*September 24, 2009*

**Physics**

A small block of mass m rests on the sloping side of a triangular block of mass M which itself rests on a horizontal table. Assuming all surfaces are frictionless, determine the magnitude of the force ->F that must be applied to M so that m remains in a fixed position ...

*September 23, 2009*

**Physics**

Mass m_A rests on a smooth horizontal surface, m_B hangs vertically. If m_A=15.0 kg and m_B=3.0 kg in the figure , determine the magnitude of the acceleration of each block.Enter your answers numerically separated by a comma. If initially m_A is at rest 1.300 m from the edge ...

*September 23, 2009*

**Physics!**

The cable supporting a 2100kg elevator has a maximum strength of 2.19×10^4 N. What maximum upward acceleration can it give the elevator without breaking?

*September 23, 2009*

**Physics**

One car has twice the maqss of a second car, but only half as much kiinetic energy. When both cars increase their speed by 7.0 s^-1 m, they then have the smae kinetic energy. What were the original speeds of the two cars? I got -16 or 2.4

*September 22, 2009*

**Physics**

I gues I'm looking at this the wrong way i do not understand the work you do to get to the answer Question: Find the air velocity of a plane that must have a realtive ground velocity of 250.0 h^-1 km norht if it encounters a wind pushing it toward the northeast at 75 h^-1 ...

*September 18, 2009*