Saturday

August 29, 2015
**Physics **

A force of 112 N acts on 35 kg box which moves at a steady speed across the floor. The force is directed 40 degrees above the ground. How to state Newton's second law using x components and y components? x: -Fa(cos40) -Ff=ma and y: -Fa(sin40)+Fn-Fg=0? How do you calculate ...
*Wednesday, March 25, 2015 by Alice*

**Physics **

The heating element in a George foreman grill is plugged into a 120-V wall socket, and 1 C of charge passes through it every 0.09 s. What is its power output, and what is the electrical energy being converted into?
*Wednesday, March 25, 2015 by Emily *

**physics**

Two converging lenses are separated by 25.0 cm. The focal length of each lens is 17.0 cm. An object is placed 35.0 cm to the left of the lens that is on the left. Determine the final image distance relative to the lens on the right.
*Wednesday, March 25, 2015 by britney*

**physics**

Two stones are thrown simultaneously, one straight upward from the base of a cliff and the other straight downward from the top of the cliff. The height of the cliff is 5.28 m. The stones are thrown with the same speed of 9.33 m/s. Find the location (above the base of the ...
*Wednesday, March 25, 2015 by Anonymous*

**physics**

At an instant when a soccer ball is in contact with the foot of the player kicking it, the horizontal or x component of the ball's acceleration is 930 m/s2 and the vertical or y component of its acceleration is 960 m/s2. The ball's mass is 0.34 kg. What is the ...
*Wednesday, March 25, 2015 by Kristyn*

**physics**

A fire hose ejects a stream of water at an angle of 31.7 ° above the horizontal. The water leaves the nozzle with a speed of 29.2 m/s. Assuming that the water behaves like a projectile, how far from a building should the fire hose be located to hit the highest possible fire?
*Wednesday, March 25, 2015 by Kristyn*

**Physics**

In the figure below, a block of mass m = 14 kg is released from rest on a frictionless incline angled of angle θ = 30°. Below the block is a spring that can be compressed 2.0 cm by a force of 270 N. The block momentarily stops when it compresses the spring by 4.6 cm. ...
*Wednesday, March 25, 2015 by Anonymous*

**physics**

A slab of wood with mass m=1.7kg floats 78% submerged.the density of water is 1000kg/m.what is the density of the wood?
*Wednesday, March 25, 2015 by eunice*

**physics**

A solid ball with a mass m=0.53kg floats in a tank of water.The ball is made of material with a density of 400kg/m^3.The density of water is 1000kg/m^3.what fraction of the ball is below waterline?
*Wednesday, March 25, 2015 by eunice*

**physics**

A fire hose ejects a stream of water at an angle of 31.7 ° above the horizontal. The water leaves the nozzle with a speed of 29.2 m/s. Assuming that the water behaves like a projectile, how far from a building should the fire hose be located to hit the highest possible fire?
*Wednesday, March 25, 2015 by Kristyn*

**physics **

a 20newton object Is pulled along a horizontal surface at a constant velocity by a 30N force. What is the coefficient of friction
*Wednesday, March 25, 2015 by Christine*

**physics**

Question Part Points Submissions Used 1 –/2.35 0/100 Total –/2.35 ... Janet wants to find the spring constant of a given spring, so she hangs the spring vertically and attaches a 0.53 kg mass to the spring's other end. If the spring stretches 3.9 cm from its ...
*Wednesday, March 25, 2015 by hannah*

**physics**

A mother rocket fired from the ground last year’s eve ejects 25% of its mass 2.0 at the at the rate if so m/s in the first second of its flight. Find the initial acceleration of the mother rocket.
*Wednesday, March 25, 2015 by ella*

**Physics**

A ball is attached to one end of a wire, the other end being fastened to the ceiling. The wire is held horizontal, and the ball is released from rest (see the drawing). It swings downward and strikes a block initially at rest on a horizontal frictionless surface. Air ...
*Wednesday, March 25, 2015 by Sia*

**Physics **

A 10kg suitcase is placed on a horizontal conveyor belt the top of which moves to the right. The coefficient of static friction between the belt and box is µs = 0.5 and that of kinetic friction is µk = 0.3. a) Sketch a free body diagram for the suitcase, showing ...
*Wednesday, March 25, 2015 by Jim*

**physics**

A mother rocket fired from the ground last year’s eve ejects 25% of its mass at the at the rate if so m/s in the first second of its flight. Find the initial acceleration of the mother rocket.
*Wednesday, March 25, 2015 by ella*

**Physics**

You're an investigator for the National Transportation Safety Board, examining a subway accident in which a train going at 80km/h collided with a slower train traveling in the same direction at 20km/h . Your job is to determine the relative speed of the collision, to help ...
*Wednesday, March 25, 2015 by Robert*

**physics**

Starting from home, you bicycle 22km north in 2.3h and then turn around and pedal straight home in 1.3h . What are your (a) displacement at the end of the first 2.3h , (b) average velocity over the first 2.3h , (c) average velocity for the homeward leg of the trip, (d) ...
*Wednesday, March 25, 2015 by tendi*

**physics**

Two strings are vibrating at the same frequency of 113 Hz. After the tension in one of the strings is decreased, an observer hears two beats each second when the strings vibrate together. Find the new frequency in the adjusted string.
*Wednesday, March 25, 2015 by romal *

**physics**

A golfer imparts a speed of 25.8 m/s to a ball, and it travels the maximum possible distance before landing on the green. The tee and the green are at the same elevation. (a) How much time does the ball spend in the air? (b) What is the longest "hole in one" that the...
*Wednesday, March 25, 2015 by Kristyn*

**physics**

A tennis ball is struck and departs from the racket horizontally with a speed of 27.7 m/s. The ball hits the court at a horizontal distance of 20.6 m from the racket. How far above the court is the tennis ball when it leaves the racket?
*Wednesday, March 25, 2015 by Kristyn*

**physics**

An object is projected from the surface of the earth with a speed of 2.73x10^4 m/s. What is its speed when it is very far from the earth? (Neglect air resistance).
*Tuesday, March 24, 2015 by Kristen*

**Physics**

Calculate the electric force between these two electrons. The value of the Coulomb constant 9 × 109 N · m2/C2 and the elemental charge is 1.6×10−19C. Answer in units of N (Newtons)
*Tuesday, March 24, 2015 by Shannon*

**Physics**

There 46.5J of elastic potential energy stored in a spring. How far is the spring stretched if the spring constant is 455N/m
*Tuesday, March 24, 2015 by Jacob*

**physics**

One end of a piano wire is wrapped around a cylindrical tuning peg and the other end is fixed in place. The tuning peg is turned so as to stretch the wire. The piano wire is made from steel (Y = 2.0x1011 N/m2). It has a radius of 0.51 mm and an unstrained length of 0.65 m. The...
*Tuesday, March 24, 2015 by miles*

**physics**

A coin with a diameter of 1.37 cm is dropped on its edge onto a horizontal surface. It starts rolling with an initial angular speed of 10.5 rad/s and rolls in a straight line without slipping. If the rotation slows with an angular deceleration of 2.34 rad/s 2 , how far does ...
*Tuesday, March 24, 2015 by chris*

**PHYSICS -urgent**

A bomber in level flight, flying at 92m/s, releases a bomb at a height of 1950m. (a) How long is it before the bomb strikes earth? (19.9s) (b) How far does it travel horizontally? (1832m) (c) What are the horizontal and vertical components of its velocity when it strikes? (...
*Tuesday, March 24, 2015 by eddie*

**Physics**

A dragster's top acceleration is 60m/s^2. If it accelerates for 3 seconds from the starting line, how fast will it be going?
*Tuesday, March 24, 2015 by Help please!*

**Physics**

The captain of a plane wishes to proceed due west. The cruising speed of the plane is 245 m/s relative to the air. A weather report indicates that a 38.0 m/s wind is blowing from south to north. In what direction should the pilot head the plane relative to the ground?
*Tuesday, March 24, 2015 by Jrom*

**Cultural Anthropology**

DESCRIBE 2 REASONS WITH EXAMPLES WHY IT IS IMPORTANT TO HAVE A STRICT CODE OF ETHICS IN ANTHROPOLOGY AND OTHER SOCIAL SCIENCES COMPARED TO MORE SCIENTIFIC DISCLIPLINES SUCH AS CHEMISTRY OR PHYSICS My textbook is Cultural anthroplogy by barbra miller and i can't find ...
*Tuesday, March 24, 2015 by breeamberr*

**Physics**

Los Angeles (32 degrees North, 119degrees West) and Atlanta (33 degrees North, 84 degrees West) are approximately at the same latitude but not longitude. If a crow were to fly between the two cities what is the approximate shortest flight distance in kilometers?
*Tuesday, March 24, 2015 by Chris*

**physics**

. A long string carries a wave; a 6-m segment of the string contains four complete wavelengths and has a mass of 180 g. The string vibrates sinusoidal with a frequency of 50 Hz and a peak-to-valley displacement of 15 cm. (The “peak-to- valley” distance is the ...
*Tuesday, March 24, 2015 by youssef*

**Physics**

Mass m1 = 0.5 kg moves with constant velocity v1i = 2.5 m/s along the x-axis and collides with mass m2 = 2.6 kg, which moves with velocity v2i = 3.1 m/s, as sketched below(completely vertical). After the collision, m1 and m2 stick together. a.) Find the angle, θ, between ...
*Tuesday, March 24, 2015 by Emma*

**PHYSICS**

A certain resistance thermometer at triple point of water is 152.0 ohms. What is the temperature of the system in degrees celsius when the resistance of the thermometer is 230.51ohms.
*Tuesday, March 24, 2015 by LOVELINE*

**Physics**

A Ferris wheel with a diameter of 35.0 m in starts from rest and achieves its maximum operational tangential speed of 2.20 m/s in a time of 15.0 s. (a) What is the magnitude of the wheel's angular acceleration? (b) What is the magnitude of the tangential acceleration after...
*Tuesday, March 24, 2015 by Alam*

**physics**

a ball was thrown vertically upward from the ground and reaches a height of 50 meters. a) with what speed was it thrown? b) how long will it remain in the air?
*Tuesday, March 24, 2015 by sandra*

**physics**

during a scienceday learners use a plastic cold drink bottle as a rocket. they use a bicycle pump to increase the bottle. when the pressure becomes high enough, the bottle is launched vertically upward into the air. the bottle returns to its original position after 3s. ignore ...
*Tuesday, March 24, 2015 by warren *

**Physics**

A 20kg box is being pushed across the floor by a constant force (90,0,0)N. The coefficient of kinetic friction for the table and box is 0.25. At t=5s the box is at location ( 8,2,-1)m, traveling with velocity (3,0,0) m/s. What is the position and velocity at t=5.6s?
*Tuesday, March 24, 2015 by reem*

**physics**

We have to do a lab in physics where we research and write on real life applications of momentum, the guidelines we have are Research Assignment: Application of Momentum in Real-Life Situations Task: Choose any real-life situation where the concept of momentum is involved and ...
*Tuesday, March 24, 2015 by Al*

**physics**

A 5.0 Ω resistor, a 9.0 Ω resistor, and a 12.0 Ω resistor are connected in parallel across a 24.0 V battery. a) What is the equivalent resistance of the circuit? Answer in units of Ω b) What is the current in the 5.0 Ω resistor? Answer in units of A
*Monday, March 23, 2015 by Danny*

**Physics - Electric Field **

Find the electric field at a point midway between 2 charges of +40.0e-9 C and +60.0E-9 C separated by a distance of 30.0 cm. My work: q1=40E-9 q2=60e-9
*Monday, March 23, 2015 by Marissa *

**Physics - Electric Fields **

Could someone please explain electric potential energy? Note: The question itself is not on my homework, but I'm having trouble understanding the theory behind my homework.
*Monday, March 23, 2015 by Jamie *

**Physics **

A cart is moving at 1.01 m/s to the left has a head-on collision with a 28.5 kg cart traveling 2.04 m/s to the right. If the velocity to the first cart is 2.99 m/s to the right, what is its mass?
*Monday, March 23, 2015 by A*

**Physics**

In 2286, Admiral Kirk and his crew were forced to use the slingshot effect in a stolen Klingon Bird-of-Prey to travel back in time to the late 20th century to retrieve two humpback whales. The stolen Klingon Bird-of-Prey traveled towards the sun at a velocity of vs while the ...
*Monday, March 23, 2015 by carolyn*

**Physics**

Consider holding a carton of milk in your hand. The force of the bicep muscle actsat an angle of 15 degrees to the vertical, while the weight of the arm and the milk both act downwards. The distance from the elbow to where the bicep muscle is attached via the distal bicep ...
*Monday, March 23, 2015 by carolyn*

**physics**

A 1kg block of wood is moving with a velocity of 10 m/s on top of a table. The coefficient of kinetic friction between the block of wood and the table is 0.1. The block of wood is a cube with sides of 12 cm. How far does the block move before coming to a stop? If momentum is ...
*Monday, March 23, 2015 by carolyn*

**Physics**

Water flows horizontally in a tapered pipe at a rate of 500 m^3/h. The area at one section of the pipe is 6500 mm² and 4000 mm² at another section. Calculate the gauge pressure at the larger section if the pressure at the smaller section is atmospheric.
*Monday, March 23, 2015 by John*

**physics**

A remote control toy car starts from rest and moves with constant unkown acceleration. After half a second it has travel 0.65m. How far has it traveled after 3 seconds?
*Monday, March 23, 2015 by michell lopez*

**physics**

If 2 objects of unequal masses are hung vertically over a frictionless pulley of negligible mass. determine the magnitude of the acceleration of the two objects and the tension in the light weight cord
*Monday, March 23, 2015 by Ebun*

**mathematical physics**

A series circuit consist of a resister with R =200 ohm, an inductor with L=1H, a capacitor with C = 0.002F, and a 12V battery.If the initial charge and current are both 0, find the charge and current at time t.
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Obtain the temperature distribution u( x,t ) in a literally insulated rod of length L if both ends on the rod are kept at 0°c and the initial temperature distribution in the bar is : u(x,0) = 6sin[πx/L]
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Obtain the Fourier for the following periodic function which has a period of 2π : f(x) = [ -1/2 (π-x) for -π<x<0,: 1/2 (π+x) for 0<x<π
*Monday, March 23, 2015 by gourav *

**physics**

Which moves faster after being accelerated from rest, (a) a 500 kg boat that has been imparted with a 10,000 N s impulse or (b) a 780 kg boat imparted with a 14,000 N s impulse?
*Monday, March 23, 2015 by Izzy*

**mathematical physics**

Separate the following partial differential equation into a set of three ODEs by the method of separation of variables. d^2/dt^2 = c^2[d^2u/dr^2+1/r du/dr+1/r^2 d^2/d theeta^2]
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Show that :(i) u=e^xsiny is a solution of Laplace's equation. (ii) u= x^2+t^2 is a solution of the wave equation.
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Solve the following ODE using the power series method (1-x^2)y"-2xy'+2y=0
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Calculate the work done by a force Vector F = y^2z^3i^+2xyz^3j^+3xy^2z^2k^ in moving an object along the path defined by the parametric equation x=t, y=t, z=t. Between the point A(t=0) and B(t=1).
*Monday, March 23, 2015 by gourav *

**Physics**

Calculate the work done on the system when 1.00 mol of gas held behind a piston expands irriversibly from a volume of 10.0dm^3 against an external pressure of 1.00 bar?
*Monday, March 23, 2015 by Andrew*

**physics**

A 20.0 kg box slides down a 12.0 m long incline at an angle of 3.0 degrees with the horizontal. A force of 50.0 N is applied to the box to try to pull it up the incline. The applied force makes an angle of 0.00 degrees to the incline. If the incline has a coefficient of ...
*Monday, March 23, 2015 by Anonymous*

**mathematical physics**

Determine the scale factors for an orthogonal coordinate system (s, t, v) whose coordinates are related to the Cartesian by the following equations: x = 2st, y = s^2-t^2, z = v Also write down an expression for the square of the arc element.
*Monday, March 23, 2015 by gourav *

**mathematical physics**

Obtain the curl of the following vector field in spherical polar coordinates: vector A = x(xi^+yj^+zk^)
*Monday, March 23, 2015 by gourav *

**Physics**

A 4.5-kg brick is suspended by a light string from a 2.0-kg pulley. The brick is released from rest and falls to the floor below. The pulley may be considered a solid disk of radius 1.5 m. What is the linear acceleration of the brick and the tension in the string?
*Monday, March 23, 2015 by Jennifer*

**Physics**

A 180-kg uniform horizontal beam is attached to a vertical wall at one end and is supported by a vertical cable at the other end making an angle of 30 degree above the x axis. What is the magnitude of the tension in the cable?
*Monday, March 23, 2015 by Jennifer*

**Physics**

A uniform plank of length 4.1 m and weight 240 N rests horizontally on two supports, with 1.1 m of the plank hanging over the right support. To what distance x can a person who weighs 445 N walk on the overhanging part of the plank before it just begins to tip?
*Monday, March 23, 2015 by Jennifer*

**Physics**

It takes a force of 53kN on the lead car of a 16-car passenger train with mass 9.1x 10^5 kg to pull it atconstant 45 m/s on level tracks. (a) What power must the locomotive provide to the lead car? (b) How much more power to the lead car than calculated in pan (c) Would be ...
*Monday, March 23, 2015 by Ben *

**Physics**

A shopper pushes a grocery cart for a distance 18 m at constant speed on level ground, against a 25 N frictional force. He pushes in a direction 24° below the horizontal. What is the work done on the cart by the shopper, in joules? Magnitude of the force, in newtons, that ...
*Sunday, March 22, 2015 by TT2014*

**Physics**

Can someone walk me through how to solve this? Any help is much appreciated! Two masses moving along a straight line undergo a front-to-back collision. The masses are m1= 60.0 kg, with initial velocity v1 = 17.0 m/s, and m2 = 26.0 kg, with initial velocity v2 = 7.0 m/s. After ...
*Sunday, March 22, 2015 by James*

**Physics**

A dog, weighing 10.0 lbs, is standing on a flatboat so that he is 20 ft from the shore. He walks 8.0 ft on the boat toward shore and then halts. The boat weighs 40 lb, and one can assume there is no friction between it and the water. How far is he from the shore at the end of ...
*Sunday, March 22, 2015 by Nora*

**Physics**

A 10-g fridge magnet is supposed to hold a 2.0-g paper on the stainless steel fridge door. The normal force of 0.19 N is insufficient to keep them in place, and the paper and magnet accelerate down the fridge at 0.150 m/s2 when the fridge door is slammed. What is the ...
*Sunday, March 22, 2015 by Trex*

**physics**

In a farm yard, a 20.0-kg light is suspended from a light beam on the end of a tall pole. The beam is supported by an arm that attaches to the beam at the suspension point of the light, as shown in the diagram below. The arm makes an angle of 50.0 with the pole. Ignore...
*Sunday, March 22, 2015 by Trex*

**physics**

21.At the airport, a person pushes a luggage cart with an applied force of 150 N [forward]. Assuming the cart and luggage have a total mass of 46.0 kg and the force of friction is 95.0 N [backward], the magnitude of the acceleration of the luggage is _____ m/s2.
*Sunday, March 22, 2015 by Trex*

**Physics **

The position of a mass oscillating on a spring is given by x = (7.0 cm) cos [2πt/(0.71 s)]. (a) What is the frequency of this motion? (b) When is the mass first at the position x = -7.0 cm?
*Sunday, March 22, 2015 by Yadan Valeton*

**Physics **

A motor boat is traveling at a speed of 2.4 m/s shuts off its engine at t=0. How far does it travel before coming to a rest if it is noted that after 3 seconds its speed has dropped to half of its original value? Assume that the drag force of the water is proportional to v. (R...
*Sunday, March 22, 2015 by Anonymous*

**Physics **

a car goes over a circular hill of 50m radius at a constant speed of 20m/sec . What is the force of the car on the 600N driver at the top of the hill.?
*Sunday, March 22, 2015 by Anonymous*

**Physics**

A 51 kg block of metal has specific heat of 222 j/kg c. how heat energy must be applied to the block of metal to raise its temperature from 10 c to 22 c?
*Sunday, March 22, 2015 by Heather *

**physics**

A solid of relative density 1.25 is found to weigh 12g in water find its weight in air
*Sunday, March 22, 2015 by mahak*

**Physics**

What is the linear speed of a child standing 0.4 m from the centre of a steadily rotating merry go around? It makes one complete revolution in 16.0 s.
*Sunday, March 22, 2015 by Bollah-braz*

**Physics**

A uniform solid sphere rolls down an incline. (a) What must be the incline angle if the linear acceleration of the center of the sphere is to have a magnitude of 0.50g?
*Sunday, March 22, 2015 by Uina*

**physics**

When are the electric field lines are parallel to each other
*Sunday, March 22, 2015 by rajeev*

**mathematical physics**

Obtain all the first and second order partial derivatives of the function: f( x, y ) = In(I+xy^2)
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Show that: (I) u = e^xsiny is a solution of Laplace's equation. (ii) u = x^2+t^2 is a solution of the wave equation.
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Solve the following ODE using the power series method (1-x^2)y"-2xy'+2y = 0
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

A series circuit consist of a resister with R = 200ohm, an inductor with L = 1H, a capacitor with C = 0.002F, and a 12V battery.If the initial charge and current are both O, Find the charge and current at time t.
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Determine the scale factors for an orthogonal coordinate system (s,t,v) whose coordinates are related to the Cartesian by the following equations: x = 2st, y = s^2-t^2, z = v.
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Show that for any scaler field phi( x,y,z ) Vector del×(vector del phi ) = vector 0
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Show that vector del(r^2) = 2vector r
*Sunday, March 22, 2015 by gourav *

**mathematical physics**

Determine whether the following vector field is incompressible or irrotational at the point (0,1,2). Vector F = [x/x^2+y^2+z^2]i^+[y/x^2+y^2+z^2]j^+[z/x^2+y^2+z^2]k^
*Sunday, March 22, 2015 by gourav *

**physics**

a 70 kg block rests on the earth's surface. How much energy is required to move the block very far from the earth, ending up at rest again?
*Sunday, March 22, 2015 by paul*

**Physics**

Two balls of equal mass (400g each) undergo a collision. One ball is initially stationary. After the collision, the velocities of the balls make angles of 22.5 degrees and 35.9 degrees relative to the original direction of the motion of the moving ball. If the initial velocity...
*Sunday, March 22, 2015 by Zobia*

**physics**

in a game of billiard , a collision occurs between two marble balls of different mass. one ball 400g is initially at rest. After the collision, this ball acquires a velocity of 1.40m/s at an angle of 37 degrees from the original direction of the motion of the other ball (500g...
*Saturday, March 21, 2015 by Zobia*

**Physics**

A 130kg mail bag hangs by a vertical rope 3.9m long. A postal worker then displaces the bag to a position 2.2m sideways from its original position, always keeping the rope taut.
*Saturday, March 21, 2015 by Kevin*

**Physics**

A rock is thrown directly upward from the edge of the roof of a building that is 35.3 meters tall. The rock misses the building on its way down, and is observed to strike the ground 4.00 seconds after being thrown. Neglect any effects of air resistance. With what speed was the...
*Saturday, March 21, 2015 by Thomas*

**Physics**

A motor boat is traveling at a speed of 2.4 m/s shuts off its engine at t=0. How far does it travel before coming to a rest if it is noted that after 3 seconds its speed has dropped to half of its original value? Assume that the drag force of the water is proportional to v. (R...
*Saturday, March 21, 2015 by Anonymous*

**Physics**

a 2.00 kg object has a velocity of 4.00i -3.00j m/s. What is the kinetic energy at this moment? What is the net work done on the object if its velocity change 6.00i +2.00j m/s
*Saturday, March 21, 2015 by Anonymous*

**Physics**

So...the question is that a coil spring has a force constant of k = 4.0 lb/in. When the spring's axis is inclined at an angle 30 degrees form horizontal, a Weight = 2.0 oz ball is propelled to a height of 6.0 ft. By how much must the spring have been compressed initially...
*Saturday, March 21, 2015 by Nora*

**Physics **

A motor boat is traveling at a speed of 2.4 m/s shuts off its engine at t=0 . How far does it travel before coming to rest after 3 seconds it's speed have dropped to half of its original value ? Assume that the drag force of the water is proportional to v ( R = -bv)
*Saturday, March 21, 2015 by rush *

**Physics **

a car goes over a circular hill of 50m radius at a constant speed of 20m/sec . What is the force of the car on the 600N driver at the top of the hill.?
*Saturday, March 21, 2015 by Anonymous*

**physics**

How many circus balloons will it take to lift a 80.0 kg person? The pressure is 1.00 atmospheres. The temperature is 298 K. The air is composed of 20.0% oxygen and 80.0% nitrogen. Each balloon is a perfect sphere, 40 cm in diameter, filled with helium gas (also at 1.00 ...
*Saturday, March 21, 2015 by Van355@*

**Physics**

A pendulum string has a length l = 4.0 ft. When the pendulum ball is released at 90 degrees to the vertical, it will swing down. A nail is located distance d below the point of suspension of the pendulum. Show that d must be at least 0.6l if the ball is to swing completely ...
*Saturday, March 21, 2015 by Nora*

**mathematical physics**

Using Green's theorum evaluate the integral [ integration from c x^2ydx-xy^2dy] where c is the closed curve along the circle. x^2+y^2 = 4
*Saturday, March 21, 2015 by gourav *