Sunday

September 21, 2014

September 21, 2014

**Recent Homework Questions About Physics**

Post a New Question | Current Questions

**physics**

A blue ball is thrown upward with an initial speed of 22.8 m/s, from a height of 0.8 meters above the ground. 2.8 seconds after the blue ball is thrown, a red ball is thrown down with an initial speed of 10.9 m/s from a height of 29.3 meters above the ground. The force of ...
*Monday, September 8, 2014 at 7:00pm*

**Physics**

Vector A has a magnitude of 13.0 units and points due west. Vector B points due north. (a) what is the magnitude of B if A+B has a magnitude of 16.8 units? (b) What is the direction of A+B relative to due west? (c) What is the magnitude of B if A-B has a magnitude of 16.8 ...
*Monday, September 8, 2014 at 6:55pm*

**Physics**

You have three balls, one is thrown upward at 30m/s, on is dropped, and one is thrown toward the ground at 20m/s. what is the acceleration of the dropped ball? Vf=0m/s + (-10m/s^2)(1) =0m/s -10m?s^2 = -10m/s a= -10m/s * 0 /1 = 0 am i on the right track.....? please help
*Monday, September 8, 2014 at 6:41pm*

**physics**

Calculate the acceleration of a ball that starts from rest, rolls down a ramp, and gains a speed of 24m/sm/s in 5.8 seconds.
*Monday, September 8, 2014 at 5:37pm*

**physics**

Calculate the distance you will travel if you maintain an average speed of 12km/h for one-half hour.
*Monday, September 8, 2014 at 5:32pm*

**Physics**

Calculate the average speed (in km/h)of Larry, who runs to the store 3.6 kilometers away in 40 minutes.
*Monday, September 8, 2014 at 5:31pm*

**Physics**

You serve a tennis ball from a height of 2.1 m above the ground. The ball leaves your racket with a speed of 19.2 m/s at an angle of 5.3° above the horizontal. The horizontal distance from the court's baseline to the net is 11.83 m, and the net is 1.07 m high. Neglect ...
*Monday, September 8, 2014 at 5:15pm*

**Physics**

On a distant planet, a freely falling object has an acceleration of 17m/s2m/s^2 . Calculate the speed that an object dropped from rest on this planet acquires in 2.0ss .
*Monday, September 8, 2014 at 5:11pm*

**physics**

Two point charges 0.600 m apart experience a repulsive force of 0.400 N. The sum of the two charges equals 1.00*10^-5 C. Find the values of the two charges.
*Monday, September 8, 2014 at 3:07pm*

**Physics**

A wind is blowing with a speed of 50 mph is a direction 40 degrees west of north. What is the westerly component of the wind's velocity? What is the northerly component of this velocity?
*Monday, September 8, 2014 at 1:26pm*

**Physics**

An object starts from rest an under a constant acceleration has traveled a displacement of 30.5 meters when it reaches a certain final velocity. The same object starts from rest, but has an acceleration which is a factor of 3.3 times smaller than the original acceleration. If ...
*Monday, September 8, 2014 at 12:14pm*

**physics **

In our country and in most of other countries ,the Celsius scale is more commonly used . Can you think of a reason for this?
*Monday, September 8, 2014 at 11:34am*

**Physics**

A boy jumps from rest, straight down from the top of a cliff. He falls halfway down to the water below in 0.620 s. How much time passes during his entire trip from the top down to the water? Ignore air resistance.
*Monday, September 8, 2014 at 10:46am*

**physics**

A stone is thrown from the top of a building upward at an angle of 30.0∘to the horizontal and with an initial speed of 20.0 m/s. If the height of the building is 45.0 m, what is the speed in m/sec of the stone just before it strikes the ground ?
*Monday, September 8, 2014 at 8:18am*

**physics**

The position of a particle as it moves along the x axis is given by x = 15eƒ{2t m, where t is in s. What is the acceleration of the particle at t = 1.0 s? 4.
*Monday, September 8, 2014 at 7:37am*

**PHYSICS**

A car moves around a 4.5 km circular track at a rate of 40.0 m/s. What is the magnitude of the force that keeps a 1000-kg car in circular motion?
*Monday, September 8, 2014 at 6:23am*

**physics**

if a electricity genreter move with the speed of 60km/h how much electricity they generate in 1 minute in volt
*Monday, September 8, 2014 at 12:12am*

**Physics**

A small rock is thrown vertically upward with a speed of 14.0m/s from the edge of the roof of a 25.0m tall building. The rock doesn't hit the building on its way back down and lands in the street below. Air resistance can be neglected. What is the speed of the rock just ...
*Sunday, September 7, 2014 at 11:56pm*

**Physics**

Two cars, A and B, travel in a straight line. The distance of A from the starting point is given as a function of time by xA(t)=αt+βt^2, with α=2.60m/s and β=1.20m/s^2. The distance of B from the starting point is xB(t)=γt^2−δt^3, with γ...
*Sunday, September 7, 2014 at 11:53pm*

**physics**

A race driver has made a pit stop to refuel. After refueling, he starts from rest and leaves the pit area with an acceleration whose magnitude is 5.4 m/s2; after 4.4 s he enters the main speedway. At the same instant, another car on the speedway and traveling at a constant ...
*Sunday, September 7, 2014 at 11:46pm*

**Physics**

A 100kg trolley is being pushed up a rough 30Â° incline by a constant force. The friction force between the incline and the trolley is 110N. (a) Determine thd value of the constant force that will move the trolley up the incline at a constant velocity of 5m/s. (b) ...
*Sunday, September 7, 2014 at 11:41pm*

**physics**

A person takes a trip, driving with a constant speed 94 km/h except for a 50 min rest stop. If the person's average velocity is 74 km/h, how far is the trip? Answer in units of km.
*Sunday, September 7, 2014 at 11:20pm*

**Physics**

Two ping-pong balls each have a mass of (1.4x10^0) g and carry a net charge of (3.99x10^0) μC. One ball is held fixed. At what height should the second ball be placed directly above the fixed ball if it is to remain there?
*Sunday, September 7, 2014 at 11:00pm*

**Physics**

Two 34 −ìC charges are attached to the opposite ends of a spring of spring constant 150 N/m and equilibrium length 50 cm. that is the question I should probably know this but my brain is fried so far all I have is Original length = 50 cm = 0.5 m Let the spring ...
*Sunday, September 7, 2014 at 10:31pm*

**Physics**

What electric field strength would store 17.5J of energy in every 9.00mm3 of space?
*Sunday, September 7, 2014 at 9:55pm*

**Physics**

A Honda Civic travels in a straight line along a road. Its distance x from a stop sign is given as a function of time t by the equation x(t)= α t^2− β t^3, where α = 1.54m/s2 and β = 5.05×10−2m/s^3 . Calculate the average velocity of the ...
*Sunday, September 7, 2014 at 9:13pm*

**Physics **

Two 0.75m -long pendulums hang side by side. The masses of the pendulum bobs are 65g and 85g . The lighter bob is pulled aside until its string is horizontal and is then released from rest. It swings down and collides elastically with the other bob at the bottom of its arc.To ...
*Sunday, September 7, 2014 at 9:01pm*

**Physics**

A car travels in the +x-direction on a straight and level road. For the first 5.00s of its motion, the average velocity of the car is V = 7.11m/s . How far does the car travel in 5.00s ? Thank you!
*Sunday, September 7, 2014 at 8:53pm*

**physics**

A rifle with a muzzle velocity of 480 m/s shoots a bullet at a target 45.6 m away. How high above the target must the rifle barrel be pointed to ensure that the bullet will hit the target? Neglect air resistance.
*Sunday, September 7, 2014 at 8:31pm*

**AP Physics C**

as she pick up her riders a bus driver traverses four successive displacements represented by the expression (-6.30 b)i-(4.00 b cos 40)i-(4.00 sin 40)j+(3.00 b cos 50)i-(3.00 b sin 50)j-(5.00 b)j here b represents one city block,a convenient unit of distance of uniform size; i...
*Sunday, September 7, 2014 at 8:10pm*

**physics**

How long will it take a cat to run 8.2m [N] at an average velocity of 3.7m/s [N]
*Sunday, September 7, 2014 at 7:21pm*

**Physics**

A 330.0 g block is dropped onto a vertical spring with a spring constant k = 234.0 N/m. The block becomes attached to the spring, and the spring compresses 0.26 m before momentarily stopping. A) While the spring is being compressed, what what is the change in the objects ...
*Sunday, September 7, 2014 at 6:55pm*

**Physics**

At one instant a bicyclist is 40 m due east of a park's flagpole, going due south with a speed of 18 m/s. Then, 23 s later, the cyclist is 55 m due north of the flagpole, going due east with a speed of 12 m/s. For the cyclist in this 23 s interval, find each of the ...
*Sunday, September 7, 2014 at 6:38pm*

**physics**

Two rockets are flying in the same direction and are side by side at the instant their retrorockets fire. Rocket A has an initial velocity of +4100 m/s, while rocket B has an initial velocity of +9400 m/s. After a time t both rockets are again side by side, the displacement of...
*Sunday, September 7, 2014 at 5:41pm*

**physics**

A ball is thrown straight up with an initial speed of 60 m/s. How high does it go? Assume the accelera- tion of gravity is 10 m/s22
*Sunday, September 7, 2014 at 4:53pm*

**college physics**

A 49-kg lead ball is dropped from the leaning tower of Pisa. The tower is 54 m high. (a) How far does the ball fall in the first 2.4 seconds of flight? (b) What is the speed of the ball after it has traveled 4.1 m downward? (c) What is the speed of the ball 1.7 s after it is ...
*Sunday, September 7, 2014 at 4:51pm*

**physics**

In getting ready to slam-dunk the ball, a basketball player starts from rest and sprints to a speed of 11.0 m/s in 2.58 s. Assuming that the player accelerates uniformly, determine the distance he runs.
*Sunday, September 7, 2014 at 4:24pm*

**physics**

Over a time interval of 2.17 years, the velocity of a planet orbiting a distant star reverses direction, changing from +19.3 km/s to -22.9 km/s. Find (a) the total change in the planet's velocity (in m/s) and (b) its average acceleration (in m/s2) during this interval. ...
*Sunday, September 7, 2014 at 4:03pm*

**Physics**

An 84.9 kg man is standing on a frictionless ice surface when he throws a 2.00kg book at 11.1m/s. With what velocity does the man move across the ice?
*Sunday, September 7, 2014 at 3:41pm*

**Physics**

A car slows from 23 m/s to 3.4 m/s at a constant rate of 2.1 m/s2. How many seconds are required before the car is traveling at 3.4 m/s?
*Sunday, September 7, 2014 at 3:31pm*

**Physics**

Two trains are approaching each other, one at 23 mph and the other at 37 mph. How far apart are they one minute before collision?
*Sunday, September 7, 2014 at 2:10pm*

**physics**

A net force of 5000.0 N accelerates a car from rest to 93.3 km/h (meter per second) in 4.1s (a)what is the mass of the car? (b) What is the weight of the car?
*Sunday, September 7, 2014 at 2:07pm*

**physics**

Due to continental drift, the North American and European continents are drifting apart at an average speed of about 3 cm per year. At this speed, how long (in years) will it take for them to drift apart by another 658.1 m?
*Sunday, September 7, 2014 at 1:46pm*

**physics**

Clint Dempsey takes a free kick and kicks a soccer ball with a mass of 440 grams at 98 miles per hour. what is the momentum
*Sunday, September 7, 2014 at 1:26pm*

**Physics**

A particle moves according to the equation x(t) = (10 m/s2) t2 where x is in meters and t is in seconds. Find the average velocity for the time interval from t1 = 2.0 s to t2 = 3 s. Answer in units of m/s. Please help! I have no idea how to set this up :(
*Sunday, September 7, 2014 at 12:58pm*

**physics**

A person swims with a speed v realative to water What dose this mean?
*Sunday, September 7, 2014 at 8:31am*

**Physics**

Two point charges are located on the y axis as follows: charge q1 = -2.50nC at y1 = -0.700m , and charge q2 = 3.30nC at the origin (y = 0). What is the magnitude of the net force exerted by these two charges on a third charge q3 = 9.00nC located at y3 = 0.250m ? What is the ...
*Sunday, September 7, 2014 at 4:18am*

**Physics**

Two small plastic spheres are given positive electrical charges. When they are 11.0cm apart, the repulsive force between them has magnitude 0.300N. What is the charge on each sphere if one sphere has four times the charge of the other?
*Sunday, September 7, 2014 at 4:16am*

**Physics**

A charge q1 = 5.00nC is placed at the origin of an xy-coordinate system, and a charge q2 = -2.00nC is placed on the positive x axis at x= 4.00cm . If a third charge q3 = 6.50nC is now placed at the point x= 4.00cm , y= 3.00cm find the x and y components of the total force ...
*Sunday, September 7, 2014 at 4:12am*

**physics**

the net external force on a golf cart is 390 n north. if the cart has a total mass of 220 kg. what is the magnitude and direction of its acceleration
*Sunday, September 7, 2014 at 2:19am*

**physics**

A spacecraft of mass 3.5 x 102kg was moving at 1.5 x 102ms-1 when its motor, operating at 8.4 x 102 kW fired for 5.0s Find the new velocity acquired by the spacecraft I dont know how to find the new velocity i found the work Power = w/t 840 x 5 = W 4200J = W Dont know what to ...
*Saturday, September 6, 2014 at 10:06pm*

**Physics**

You toss a tennis ball straight upward. At the moment it leaves your hand it is at a height of 1.5 m above the ground, and it is moving at a speed of 8.0 m/s. (a) How much time does it take for the tennis ball to reach its maximum height? (b) What is the maximum height above ...
*Saturday, September 6, 2014 at 7:53pm*

**Physics for Technology**

I have been out of school 27 years; no Algebra or Trigonometry training: only remedial math. This class is part of a Diploma program, no placement test required - I am out of my depth. I had a tutor for an hour last Tues., with another appt. this Tues. Yet, like I told my ...
*Saturday, September 6, 2014 at 7:36pm*

**physics**

In reaching her destination, a backpacker walks with an average velocity of 1.22 m/s, due west. This average velocity results, because she hikes for 5.61 km with an average velocity of 2.69 m/s due west, turns around, and hikes with an average velocity of 0.367 m/s due east. ...
*Saturday, September 6, 2014 at 7:26pm*

**physics**

A skateboarder shoots off a ramp with a velocity of 6.4 m/s, directed at an angle of 54° above the horizontal. The end of the ramp is 1.4 m above the ground. Let the x axis be parallel to the ground, the +y direction be vertically upward, and take as the origin the point ...
*Saturday, September 6, 2014 at 7:14pm*

**Physics II**

What is the sign and magnitude of a point charge that produces a potential of -2.00 V at a distance of 3.00 mm?
*Saturday, September 6, 2014 at 3:20pm*

**Physics II**

What is the sign and magnitude of a point charge that produces a potential of -2.00 V at a distance of 3.00 mm?
*Saturday, September 6, 2014 at 3:15pm*

**Physics**

A wooden bridge crossing a canyon consists of a plank with length density λ = 2 kg/m suspended at h = 10.0 m below a tree branch by two ropes of length L = 2h and with a maximum rated tension of 2000 N, which are attached to the ends of the plank, as shown in the figure. ...
*Saturday, September 6, 2014 at 12:39pm*

**physics**

A flat circular plate of copper has a radius of 0.278 m and a mass of 42.6 kg. What is the thickness of the plate? answer in units of m
*Saturday, September 6, 2014 at 12:31pm*

**physics**

Two objects with masses 2.0 and 3.0 kg move toward each other, both with speeds V0 = 5.0 m/s. They collide head on and stick together. (a) Calculate their final velocity. (b) Calculate the amount of kinetic energy lost during the process. (c) Suppose the two masses approach ...
*Saturday, September 6, 2014 at 12:29pm*

**Physics Help!!!!**

Describe what it means (describe the motion) if the acceleration vector has the same direction as the velocity vectors, and what it means if the acceleration vector has the opposite direction as the velocity vectors. Consider all four possibilities and explain what would ...
*Saturday, September 6, 2014 at 11:20am*

**physics**

A bus accelerates at 1.4 m/s2 from rest for 14 s. It then travels at constant speed for 23 s, after which it slows to a stop with an acceleration of magnitude 1.3 m/s2.
*Saturday, September 6, 2014 at 11:19am*

**Physics**

1.A bus travels 400 m between two stops. It starts from rest and accelerates at 1.50 m/s^2 until it reaches a velocity of 9.00 m/s. The bus continues at this velocity and then decelerates at 2 m/s^2 until it comes to a halt. Find the total time required for the journey. 2.A 28...
*Saturday, September 6, 2014 at 3:11am*

**Physics**

A ball is thrown vertically upward from the ground with a speed of 36.0 m/s.Suppose the acceleration of gravity were only 2.00 m/s^2 instead of 9.80 m/s^2 a)At what time does it have a velocity of 12.0 m/s upward? b)At what time does it have a velocity of 12.0 m/s downward? c)...
*Saturday, September 6, 2014 at 3:00am*

**Physics**

What is the connection between Weber’s Law, Fechner’s Law, and Steven’s Power Law
*Saturday, September 6, 2014 at 2:00am*

**physics**

a fire hose hold near the ground shoots water at speed of 6.8 m/s at what angle(s) should the nozzle point in order that the water land 2 dm away why are there two diffent angles?
*Saturday, September 6, 2014 at 1:39am*

**Physics Help!!!!**

Describe what it means (describe the motion) if the acceleration vector has the same direction as the velocity vectors, and what it means if the acceleration vector has the opposite direction as the velocity vectors. Consider all four possibilities and explain what would ...
*Friday, September 5, 2014 at 11:54pm*

**Physics**

Two small pith balls, each of mass m = 17.4 g, are suspended from the ceiling of the physics lab by 1.2 m long fine strings and are not moving. If the angle which each string makes with the vertical is = 17.9°, and the charges on the two balls are equal, what is the ...
*Friday, September 5, 2014 at 11:22pm*

**Physics**

Instructions for finding a buried treasure include the following: Go 745.6 paces at 298◦, turn to 204◦ and walk 178 paces, then travel 490 paces at 55◦ Find the magnitude of the resultant displacement from the starting point. Answer in Units of paces. (Part ...
*Friday, September 5, 2014 at 11:20pm*

**physics**

On a safari, a team of naturalists sets out toward a research station located 5.54 km away in a direction 47.9 ° north of east. After traveling in a straight line for 1.29 km, they stop and discover that they have been traveling 24.6 ° north of east, because their ...
*Friday, September 5, 2014 at 10:53pm*

**AP Physics **

A bowling ball traveling with constant speed hits the pins at the end of a bowling lane 16.5 m long. The bowler hears the sound of the ball hitting the pins 2.90 s after the ball is released from his hands. What is the speed of the ball? The speed of sound is 340 m/s. Answer ...
*Friday, September 5, 2014 at 10:44pm*

**AP Physics **

Two locomotives approach each other on parallel tracks. Each has a speed of v = 85 km/h with respect to the ground. If they are initially d = 7.0 km apart, how long will it be before they reach each other?
*Friday, September 5, 2014 at 10:44pm*

**AP Physics **

A car traveling 92 km/h is 130 m behind a truck traveling 75 km/h. How long will it take the car to reach the truck?
*Friday, September 5, 2014 at 10:43pm*

**Physics**

A cannon fires a shell straight upward; 2.1 s after it is launched, the shell is moving upward with a speed of 20 m/s. Assuming air resistance is negligible, find the speed (magnitude of velocity) of the shell at launch and 4.7 s after the launch.
*Friday, September 5, 2014 at 7:18pm*

**physics**

Two forces are applied to a tree stump to pull it out of the ground. Force A has a magnitude of 2880 newtons (N) and points 42.0 ° south of east, while force B has a magnitude of 4360 N and points due south. Using the component method, find the (a) magnitude and (b) ...
*Friday, September 5, 2014 at 7:17pm*

**Physics, Electricity and Magnetism, Sciences**

Two small pith balls, each of mass m = 17.4 g, are suspended from the ceiling of the physics lab by 1.2 m long fine strings and are not moving. If the angle which each string makes with the vertical is = 17.9°, and the charges on the two balls are equal, what is the ...
*Friday, September 5, 2014 at 7:15pm*

**Physics **

Two bicyclists, starting at the same place, are riding toward the same campground by different routes. One cyclist rides 1030 m due east and then turns due north and travels another 1480 m before reaching the campground. The second cyclist starts out by heading due north for ...
*Friday, September 5, 2014 at 7:12pm*

**Physics**

A ball is thrown from the ground. Its velocity after 4 ^ ^ seconds is (15x -3y ) m/s. the range of the ball is 205 m. 189 m. 111 m. 98 m.
*Friday, September 5, 2014 at 6:54pm*

**Physics**

A flight traffic controller is watching two planes. One is 20.0 km away in a direction 35.0º west of north at an altitude of 1650 m. The other is 18.0 km away in a direction 75.0º north of east at an altitude of 1420 m. How far apart are the two planes? Ax = 20.0km*...
*Friday, September 5, 2014 at 6:27pm*

**Physics**

Should a veterinarian be skeptical if someone said that her adult collie weighed 40.0N ? Should a nurse question a medical chart which showed that an average-looking patient had a mass of 200kg ?
*Friday, September 5, 2014 at 5:54pm*

**Physics**

X=1/2at^2 Solve for a Solve for t Can you please show me how to do this Thank u
*Friday, September 5, 2014 at 4:45pm*

**Physics**

A speeding motorcyclist is traveling at a constant speed of 31.1 m/s when he passes a police car parked on the side of the road. The radar, positioned in the police car's rear window, measures the speed of the motorcycle. At the instant the motorcycle passes the police car...
*Friday, September 5, 2014 at 2:27pm*

**Physics**

A rock is dropped into a deep hole and 2.2 s later the sound of striking the bottom is heard. If the speed of sound is 340 m/s, what is the depth of the hole?
*Friday, September 5, 2014 at 1:30pm*

**Physics(Need Help please)**

Four equal charged +Q are placed at the corners of a square of side a. Find the electric field strength at the midpoint of one side. Express your answer in terms of Q, a, and the constant k
*Friday, September 5, 2014 at 12:44pm*

**Physics**

Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the naturally occuring electrons is removed. The radius of the orbit is 2.26 × 10-11 m. Determine the magnitude of the electron's ...
*Friday, September 5, 2014 at 9:00am*

**AP Physics**

A jogger runs in a straight line with an average velocity of 7.7 m/s for 4.5 minutes, and then with an average velocity of 2.8 m/s for 2.8 minutes. What is her total displacement? Answer in units of m.
*Thursday, September 4, 2014 at 9:49pm*

**physics**

a pitched ball is hit by a batter at a 45 degree angle and it just clears the outfield fence, 110m away. If the fence is at the same height as the pitch, find the velocity of the ball when it left the bat. Ignore air resistance.
*Thursday, September 4, 2014 at 8:26pm*

**Physics**

A sailboat travels 45km eastward at a speed of 20km/hr. The wind then drops, and the boat continues due east with a speed of 15km/hr for 25km. a.How long did it take the boat to travel 55km? b. What was the average velocity for the trip?
*Thursday, September 4, 2014 at 8:17pm*

**Physics**

A sailboat travels 45km eastward at a speed of 20km/hr. The wind then drops, and the boat continues due east with a speed of 15km/hr for 25km.
*Thursday, September 4, 2014 at 8:15pm*

**Physics**

Suppose a single electron orbits about a nucleus containing two protons (+2e), as would be the case for a helium atom from which one of the naturally occuring electrons is removed. The radius of the orbit is 2.26 × 10-11 m. Determine the magnitude of the electron's ...
*Thursday, September 4, 2014 at 7:37pm*

**Physics**

For any given quadrupole, let the charges be +q, −q, +q, and −q at the corners of the square, and l be the side of the square. Calculate approximately the electric potential and the electric field far away from the quadrupole, IN THE THREE-DIMENSIONAL SPACE. You ...
*Thursday, September 4, 2014 at 3:48pm*

**Physics**

A sphere of radius R has inhomogeneous charge distribution on its surface. Its surface charge density is σ = σ0 cos θ, where σ0 is a positive constant, and θ is the angle from the “north pole” to the point of interest and satisfies 0 ≤...
*Thursday, September 4, 2014 at 3:47pm*

**physics**

A player kicks a soccer ball from ground level and sends it flying at an angle of 30 degrees at a speed of 26 m/s. How long was the ball in the air? Round the answer to the nearest tenth of a second.
*Thursday, September 4, 2014 at 3:18pm*

**physics**

A stone is launched straight up by a slingshot. Its initial speed is 20.6 m/s and the stone is 1.59 m above the ground when launched. How high above the ground does the stone rise? How much time elapses before the stone hits the ground?
*Thursday, September 4, 2014 at 1:15pm*

**Physics**

The brightness of a light source at a distance of 100m from the source is 40 units. What would be the brightness if the distance is reduced to 50m?
*Thursday, September 4, 2014 at 1:04pm*

**physics**

Two identical small spherical conductors (point charges), separated by 0.6 m, carry a total charge of 200 mu or micro CC. They repel one another with a force of 120 N. (For the universal constant k use the value 8.99 times 109 N m2/C2.) so I used q1 + q2= 200e-6C and q1*q2= Fr...
*Thursday, September 4, 2014 at 11:42am*

**Physics**

An object has a initial velocity of 10 m/s in the positive x direction. Under a constant acceleration it stops after undergoing a displacement of 148.3 m in the positive x direction. Because it is still under the same acceleration it then travels back in the negative in the x ...
*Thursday, September 4, 2014 at 11:39am*

**Physics**

'An air rifle pellet of mass 2g is fired into a block of plasticine mounted on a model railway truck. the truck and plasticine have a mass of .1kg. The truck moves off after the pellet hits the plasticine with an initial velocity of .8m/s. calculate the momentum of the ...
*Thursday, September 4, 2014 at 8:44am*

**physics**

A car is moving at 90 km/h when the driver notices an animal that is about to cross the road 100 m away and he decides to apply the brakes. The reaction time of the driver is 0.3 s. Calculate the acceleration of the car when it stopped and the time taken from the time the ...
*Thursday, September 4, 2014 at 7:01am*

**Physics**

Two identical pellet guns are fired simultaneously from the edge of a cliff. These guns impart an initial speed of 36.3 m/s to each pellet. Gun A is fired straight upward, with the pellet going up and then falling back down, eventually hitting the ground beneath the cliff. Gun...
*Thursday, September 4, 2014 at 4:12am*

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