Monday

April 27, 2015

April 27, 2015

**physics**

would someone in a lift feel lighter or heavier as it accelerated upwards? explain your answer.
*Monday, February 9, 2015 at 5:40am*

**physics**

A lift of mass 1500 kg is raised by means of a rope passing round a drum of diameter 1.50 m. Given that the lift is accelerating upwards at 0.255 m s-2, draw a free body diagram of the lift, calculate the tension in the rope, the moment applied to the drum and the angular ...
*Monday, February 9, 2015 at 5:39am*

**Physics**

I am reviewing for a test and I don't know how to attempt this question. Could someone please work through this problem and then have the general steps that I need to take to solve the question? Here is the question: A rocket expels gases at a rate of 1.30 x 10^3 kg/s with...
*Monday, February 9, 2015 at 2:18am*

**College Physics **

A sled at rest is suddenly pulled in three horizontal directions at the same time, but it does not move. Paul pulls to the northeast with a force of 31 lb. Johnny pulls at an angle of 36° south of due west with a force of 52 lb. Connie pulls with a force to be determined. ...
*Monday, February 9, 2015 at 1:25am*

**Physics**

I am reviewing for a test and I don't know how to attempt this question. Could someone please work through this problem and then have the general steps that I need to take to solve the question? Here is the question: A rocket expels gases at a rate of 1.30 x 10^3 kg/s with...
*Sunday, February 8, 2015 at 11:47pm*

**physics **

You work at a garden store for the summer. You lift a bag of fertilizer with a force of 122 N, and it moves upward with an acceleration of 0.760 m/s2.
*Sunday, February 8, 2015 at 11:30pm*

**physics **

A 2011 kg elevator moves with an upward acceleration of 1.9 m/s2. What is the tension in the cable that supports the elevator?
*Sunday, February 8, 2015 at 11:28pm*

**Physics **

A rope is attached from a truck to a 1403 kg car. The rope will break if the tension is greater than 2375 N. Neglecting friction, what is the maximum possible acceleration of the truck if the rope does not break? m/s2 If the truck can reach 30 mph within 7.5 s, should the ...
*Sunday, February 8, 2015 at 11:27pm*

**physics**

REALLY NEED HELP WITH THIS PLEASE. One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1....
*Sunday, February 8, 2015 at 10:52pm*

**Physics**

Help I don't understand how to do this homework question, we didn't go over any like it in class. A car has an average speed of 80.0km/h for 1 hour, then an average speed of 90.0km/h for 2 hours during a 3 hour trip. what was the average speed for the 3 hour trip?
*Sunday, February 8, 2015 at 10:29pm*

**Physics Dynamics**

A 4-kg block is connected by means of a massless rope to a 2-kg block. What is the magnitude of the acceleration if the coefficient of kinetic friction between the 4-kg block and the surface is 0.20? Note : The 4kg block is on the table, the pulley is on the edge and the 2kg ...
*Sunday, February 8, 2015 at 10:26pm*

**Physics Dynamics**

A 5.0-kg box is pulled horizontally with a 45-N force that makes angle of 40 degree with the horizontal. The coefficient of kinetic friction of the surface is 0.20. What is the magnitude of the acceleration of the box?
*Sunday, February 8, 2015 at 10:24pm*

**Physics Dynamics**

A 10-kg block is pushed against a vertical wall by a horizontal force of 100 N. What is the coefficient of static friction between the block and the wall if the block is about to slide down?
*Sunday, February 8, 2015 at 10:23pm*

**physics **

A tennis ball (mass 57.0 g) moves toward the player's racquet at 46.4 m/s. It is in contact with the racquet for 3.60 ms, after which it moves in the opposite direction at 49.8 m/s. What is the average force on the ball due to the racquet? (Assume the ball is moving in the...
*Sunday, February 8, 2015 at 9:34pm*

**Physics**

A projectile is launched at 5.4 m/s with an initial angle of 22 degrees from an initial height of 2.6 meters. Where will it land? How fast, and at what angle will it be going when it hits the ground?
*Sunday, February 8, 2015 at 9:02pm*

**physics**

an arrangement of four disks are suspended by cords. The longer, top cord loops over a frictionless pulley and pulls with a force of magnitude 81.2 N on the wall to which it is attached. The tensions in the shorter cords are T1 = 62.7 N, T2 = 33.6 N, and T3 = 8.5 N. What are ...
*Sunday, February 8, 2015 at 8:41pm*

**physics **

In a game against the White Sox, baseball pitcher Nolan Ryan threw a pitch measured at 44.8 m/s. If it was 18.4 m from Nolan's position on the pitcher's mound to home plate, how long did it take the ball to get to the batter waiting at home plate? Treat the ball's ...
*Sunday, February 8, 2015 at 8:37pm*

**Physics **

Can someone please help me solve this question please: In the following position as a function of time equation, find the units of the constants A, B, and C. Where x is the position and has units of L, and v is velocity, and t is time. x = Av + Bt^2 + C Thank you.
*Sunday, February 8, 2015 at 8:33pm*

**Physics **

Why are household lamps are not connected series?
*Sunday, February 8, 2015 at 8:31pm*

**physics**

One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help...
*Sunday, February 8, 2015 at 8:14pm*

**physics**

isolate for f 1/di = 1/f - 1/do show all the steps pls
*Sunday, February 8, 2015 at 7:57pm*

**physics**

A 0.60 kg object with an initial velocity of 3.0 m/s in the positive x direction is acted on by a force in the direction of motion. The force does +2.5 J of work. What is the final velocity of the object?
*Sunday, February 8, 2015 at 7:45pm*

**physics**

A wheel starts from rest and rotates with constant angular acceleration to an angular speed of 9.3 rad/s in 1.39 s. Find the magnitude of the angular acceleration on the wheel
*Sunday, February 8, 2015 at 7:35pm*

**Physics**

One gram of palladium has 5.66×10^21 atoms, and each palladium atom has 46 electrons. How many electrons are contained in 7.00g of palladium? The elemental charge is1.6×10^−19C. Answer in units of electrons. The answer is 1.82252x10^24 for Part A. i need help...
*Sunday, February 8, 2015 at 7:28pm*

**physics**

a boy of mass 40kg and a girl of 30kg play on a see saw of negligible weight.if the boy sits 270cm from the pivot of the see-saw where must the girl sit to make it balance
*Sunday, February 8, 2015 at 6:58pm*

**physics**

isolate for t s = ut + 1/2at^2 please show all ur steps
*Sunday, February 8, 2015 at 6:57pm*

**Physics **

A car traveling 85km/h slows down at a constant 0.52m/s2 just by "letting up on the gas." Calculate the distance the car coasts before it stops.
*Sunday, February 8, 2015 at 4:52pm*

**physics**

The drawing shows a square, each side of which has a length of L = 0.250 m. Two different positive charges q1 and q2 are fixed at the corners of the square. Find the electric potential energy of a third charge q3 = -7.00 x 10-9 C placed at corner A and then at corner B.
*Sunday, February 8, 2015 at 3:45pm*

**Physics **

A light string is attached to both a hanging mass m1 = 5 kg and to a pulley of mass m2= 6 kg, and radius R = 0.75 m. If the pulley is a solid disc rotating about its center with a moment of inertia of I = 0.5*m2R2, and the string does not slip on the pulley, (a) what is the ...
*Sunday, February 8, 2015 at 2:44pm*

**physics**

A man stands at the midpoint between two speakers that are broadcasting an amplified static hiss uniformly in all directions. The speakers are 37.0 m apart and the total power of the sound coming from each speaker is 0.448 W. Find the total sound intensity the man hears when (...
*Sunday, February 8, 2015 at 2:23pm*

**physics**

Starting from rest, a 11.70 kg suitcase slides 3.14 m down a frictionless ramp inclined at 40° from the floor. The suitcase then slides an additional 4.68 m along the floor before coming to a stop. (a) Determine the suitcase's speed at the bottom of the ramp. (b) ...
*Sunday, February 8, 2015 at 2:14pm*

**Physics**

A uniform rod of weight 5N and lenght 1m is pivoted at a point of 20 cm from one of its ends. A weight is hung from the other end so that te rod balances horizontally. What is the value of the weight? How do I find it if I don't know the weight at the other end?
*Sunday, February 8, 2015 at 11:32am*

**physics**

If there is a constant towing force of 1.5 kN, how long would it take a tow truck to tow a 1400 kg car from rest to 52 km/h? (Assume a rolling resistance of 215 N).
*Sunday, February 8, 2015 at 9:50am*

**physics**

In the lab, a relativistic proton has a momentum of 1.00 × 10-19 kg · m/s and a rest energy of 0.150 nJ. What is the speed of the proton in the lab? (c = 3.00 × 108 m/s, m proton = 1.67 × 10-27 kg): *
*Sunday, February 8, 2015 at 4:43am*

**physics**

3. Calculate the magnitude of the force required to cause an anterior dislocation of the glenohumeral joint given that he force has a lever arm of 52 cm, the maximum magnitude of the resistance force is 1080 N and the resistance force has a lever arm of 4.3 cm.
*Sunday, February 8, 2015 at 2:29am*

**Physics**

Can someone show me and explain a step by step process how to do this problem? Thanks 1) Two equal but opposite charges re separated by a distance d. Determine a formula for VBA = VB – VA for points B and A on the line between the charges situated as shown. |<...
*Sunday, February 8, 2015 at 1:50am*

**Physics**

I don't really know where to start on the problem. Would I use V = k(q/r)? But what would I do afterwards. Much explanation on how to go about the problem is much appreciated. Thank you. 1) Three point charges are arranged at the corner of a square of side l. What is the ...
*Sunday, February 8, 2015 at 12:36am*

**physics**

A 66-kg baseball player slides into third base. He starts his slide at a speed of 4.3 m/s and his speed is zero just as he reaches the base. If the coefficient of friction between his clothes and the surface of the baseball infield is 0.60, determine the following. (a) ...
*Sunday, February 8, 2015 at 12:27am*

**physics**

A baseball (m = 145 g) traveling 20 m/s moves a fielder's glove backward 25 cm when the ball is caught. What was the average force exerted by the ball on the glove? Magnitude N Direction in the direction opposite to the ball's motion in the direction of the ball's ...
*Saturday, February 7, 2015 at 10:47pm*

**physics**

How much work must be done to stop a 1070 kg car traveling at 111 km/h?
*Saturday, February 7, 2015 at 10:02pm*

**physics**

The velocity-versus-time graph is shown for a particle moving along the x-axis. Its initial position is x0 = 1.8m at t0 =0s. Part A What is the particle's position at t=1.0s? Part B What is the particle's acceleration at t= 1.0s? Part C What is the particle's ...
*Saturday, February 7, 2015 at 9:28pm*

**physics**

A 0.25 kg particle moves along an x axis according to x(t) = - 10 + 3 t + 2 t2 - 5 t3, with x in meters and t in seconds. In unit-vector notation, what is the net force acting on the particle at t = 3.6 s ? Give an expression for the (a) x, (b) y and (c) z components.
*Saturday, February 7, 2015 at 7:02pm*

**Physics**

The blocks A and B are connected by a piece of spring. Block B rests on a smooth inclined plane of 35° and block A hangs vertically. Calculate the acceleration of the system if the mass of block A is 1.06 kg and that of block B is 6.4 kg.
*Saturday, February 7, 2015 at 5:46pm*

**Physics**

A vector has magnitude 58.0 units and is inclined to the positive axis of x at 42.0°. Vector has magnitude 36.0 units and is inclined to the positive axis of x at 121°. Vector has magnitude 40.0 units and is inclined to the positive axis of x at 53.0°. Use the ...
*Saturday, February 7, 2015 at 5:42pm*

**Physics**

A river flows at a speed of 4.60 m/s. A boat, capable of moving with a speed of 5.80 m/s in still water is rowed across the river at an angle of 53.0° to the river flow. Calculate the resultant velocity with which the boat moves and the angle that its resultant motion ...
*Saturday, February 7, 2015 at 5:42pm*

**Physics**

An airplane has to fly eastward to a destination 856 km away. If wind is blowing at 18.0 m/s northward and the air speed of the plane is 161 m/s, in what direction should the plane head to reach its destination?
*Saturday, February 7, 2015 at 5:41pm*

**Physics**

The blocks A and B are connected by a piece of spring. Block B rests on an inclined plane of 40° and block A hangs vertically. The coefficient of kinetic friction between block A and the inclined plane is 0.29. Calculate the acceleration of the system if the mass of block ...
*Saturday, February 7, 2015 at 5:40pm*

**Physics**

An athlete runs 2.76 km east, then turns south and runs another 0.85 km. What is the magnitude of his displacement?
*Saturday, February 7, 2015 at 5:38pm*

**Physics**

Find the magnitude of the sum of two forces, one 24 N and the other 9 N, when the angle between them is 60.0o.
*Saturday, February 7, 2015 at 5:37pm*

**Physics**

What should be the angle between two vectors of magnitudes 4.10 and 4.40 units, so that their resultant has a magnitude of 3.90 units?
*Saturday, February 7, 2015 at 5:37pm*

**Physics**

The blocks A and B are connected by a piece of spring. Block B rests on a smooth inclined plane of 35° and block A hangs vertically. Calculate the acceleration of the system if the mass of block A is 1.06 kg and that of block B is 6.4 kg
*Saturday, February 7, 2015 at 5:36pm*

**Physics**

A mass of 0.3 kg is attached to the end of a massless spring of spring constant 0.25 N/m. It is released from rest (t=0). After 0.7 s, the speed of the mass is measured to be 2.0 m/s. What is the amplitude of oscillation?
*Saturday, February 7, 2015 at 4:17pm*

**Physics**

A particle of charge +18.5C and mass 4.84 × 10-5 kg is released from rest in a region where there is a constant electric field of +578 N/C. What is the displacement of the particle after a time of 1.89 × 10-2 s? 1) F=Eq 2) a=F/m 3) d=vt+1/2at^2 1) F= 10693 N 2) a=...
*Saturday, February 7, 2015 at 3:43pm*

**Physics**

A 45.0 g ball of copper has a net charge of 2.3 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)
*Saturday, February 7, 2015 at 12:38pm*

**Physics**

Two identical pellet guns are fired simultaneously from the edge of a cliff. These guns impart an initial speed of 27.3 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...
*Saturday, February 7, 2015 at 9:44am*

**Physics**

How much is needed to melt an ice cube, 3 centimeters on each side at 0 degree celcius?
*Saturday, February 7, 2015 at 5:08am*

**Physics**

A soccer player kicks the ball toward a goal that is 23.0 m in front of him. The ball leaves his foot at a speed of 17.6 m/s and an angle of 29.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of the net.
*Friday, February 6, 2015 at 11:27pm*

**Physics**

A boy standing in a ditch throws a baseball upward toward his father. The ball leaves his hand at ground level, with an initial speed of 16.0 m/s,at an angle of θ = 51°, from the horizontal. The boy's father reaches up and catches the ball over his head, at a ...
*Friday, February 6, 2015 at 11:03pm*

**Physics**

Determine the banking angle needed to make a high-speed turn off a highway exit ramp with a radius of 720 m if the vehicle is travelling at 80 km/h. Assume there is no friction.
*Friday, February 6, 2015 at 7:59pm*

**Physics**

A football punter accelerates a 0.59 kg football from rest to a speed of 8.4 m/s in 0.17s. What constant force does the punter exert on the ball? Answer in units of N
*Friday, February 6, 2015 at 7:09pm*

**Physics**

A bowling ball of mass 3.5 kg moves in a straight line at 4.48 m/s. How fast must a Ping-Pong ball of mass 3.456 g move in a straight line so that the two balls have the same momentum? Answer in units of m/s.
*Friday, February 6, 2015 at 7:08pm*

**Physics**

A constant force is exerted for a short time interval on a cart that is initially at rest on an air track. This force gives the cart a certain final speed. Suppose we repeat the experiment but, instead of starting from rest, the cart is already moving with constant speed in ...
*Friday, February 6, 2015 at 7:06pm*

**College Physics**

What is the centripetal force acting on an object with a mass of 20 kg moving at a velocity of 10 m/s in a circle with a diameter of 5 m? When the object is moving with circular motion, are the forces balanced on the object? Why or why not?
*Friday, February 6, 2015 at 6:34pm*

**College Physics**

A rope can withstand a maximum tension force of 500N before breaking. If we use the rope to pull a 24 kg bucket of water from a well, what is the maximum acceleration upward we can use without breaking the rope?
*Friday, February 6, 2015 at 6:33pm*

**College Physics**

A 750 kg rocket accelerates straight upward from the ground at 60 m/s2. What is the force (thrust) provided by the engine?
*Friday, February 6, 2015 at 6:33pm*

**College Physics**

Human nerve impulses travel at about 10 m/s. Estimate the minimum reaction time from the moment you perceive an obstacle in front of your car and the moment that your foot receives the command to press on the brakes. Consider your height as 1.73m. If the car is traveling at ...
*Friday, February 6, 2015 at 6:32pm*

**College Physics**

Find (a) the magnitude and (b) the direction of the net force on an object given that the following forces act on the object at the same time: 10N east, 20N down, 20N west, 30N down, and 20N up.
*Friday, February 6, 2015 at 6:31pm*

**physics**

Assume that there is no friction between m2 and the incline, that m2 = 1.8 kg, m1 = 1.4 kg, the radius of the pulley is 0.10 m, the moment of inertia of the pulley is 3.6 kg m2, and θ = 27.0°. Mass 1 is hanging vertically while mass 2 is on the incline. After mass 2 ...
*Friday, February 6, 2015 at 5:41pm*

**physics**

Two 1.30-V batteries-with their positive terminals in the same direction-are inserted in series into the barrel of a flashlight. One battery has an internal resistance of 0.182Ω, the other an internal resistance of 0.139Ω. When the switch is closed, a current of ...
*Friday, February 6, 2015 at 5:10pm*

**physics**

A copper cable is to be designed to carry a current of 280A with a power loss of only 2.70W/m. What is the required radius of the copper cable? Answer in units of cm and use 1.7x10-8 Ωm for the resistivity of copper.
*Friday, February 6, 2015 at 2:49pm*

**integrated chemistry and physics**

In a water molecule, two hydrogen atoms bind to one oxygen atom. How many lone pairs of electrons will be shown around each hydrogen atom in the Lewis structure of water?
*Friday, February 6, 2015 at 12:29pm*

**physics (gravitation)**

At what height above the surface of the earth does the acceleration due to gravity reduces by 64% .radius of earth 6400 km
*Friday, February 6, 2015 at 12:13pm*

**physics**

A wheel has a rotational velocity of 18·rad/s counterclockwise. You place you hand against the wheel and the friction between your hand and the rim stops it. (a) If it takes 4·s to stop the wheel, what is its rotational acceleration? rad/s2 (b) How far does the ...
*Friday, February 6, 2015 at 11:24am*

**Physics **

A weight suspended from a spring is seen to bob up and down over a distance of 11 cm twice each second. What is its frequency? Answer in units of Hz. 002 (part 2 of 3) 10.0 points What is its period? Answer in units of s. 003 (part 3 of 3) 10.0 points What is its amplitude? ...
*Friday, February 6, 2015 at 10:34am*

**Physics**

A stationary observer hears a sound with a frequency of 450 Hz from an approaching car. If the car emits the sound at a frequency of 360 Hz, what would be the speed of the car? (Speed of sound 340 m/s)
*Friday, February 6, 2015 at 8:52am*

**physics**

Four identical point charges (+2.51 nC) are placed at the corners of a rectangle, which measures 4.00 m by 7.00 m. If the electric potential is taken to be zero at infinity, what is the potential at the geometric center of this rectangle?
*Friday, February 6, 2015 at 1:34am*

**physics**

An object falls a distance h from rest. If it travels 0.45h in the last 1.00 s, find the time and the height of its fall.
*Friday, February 6, 2015 at 12:54am*

**physics**

A stone is dropped into a river from a bridge 43.8 m above the water. Another stone is thrown vertically down 1.65 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?
*Friday, February 6, 2015 at 12:52am*

**physics**

The figure gives the acceleration a versus time t for a particle moving along an x axis. The a-axis scale is set by as = 15.0 m/s^2. At t = -2.0 s, the particle's velocity is 7.00 m/s. What is its velocity at t = 6.0 s?
*Friday, February 6, 2015 at 12:30am*

**Physics**

Determine the ratio of Earth's gravitational force exerted on an 80-kg person when at Earth's surface and when 1000km above Earth's surface. The radius of Earth is 6370 km. I have tried (6370)^2/(7370)^2 = 0.747 and it is wrong??
*Thursday, February 5, 2015 at 10:57pm*

**Physics**

3 kg object is fastened to a light spring with the intervening cord passing over a pulley. The pulley is frictionless and it's inertia may been neglected. The object is released from rest when the spring is unstretched. If the object drops 10 cm before stopping find the ...
*Thursday, February 5, 2015 at 10:51pm*

**Physics **

A weight suspended from a spring is seen to bob up and down over a distance of 11 cm twice each second.
*Thursday, February 5, 2015 at 8:39pm*

**physics**

A person walks up a stalled 15 m long escalator in 110 s. When standing on the same escalator, now moving, the person is carried up in 70 s. How much time would it take that person to walk up the moving escalator?
*Thursday, February 5, 2015 at 7:56pm*

**Physics**

A wildlife researcher is tracking a flock of geese. The geese fly 5.0km due west, then turn toward the north by 35∘ and fly another 3.0km . How far west are they of their initial position? What is the magnitude of their displacement?
*Thursday, February 5, 2015 at 6:45pm*

**Physics**

If a 65 kg sprinter can accelerate from a standing start to a speed of 12 m/s in 3 s, what average power is generated?
*Thursday, February 5, 2015 at 6:31pm*

**PHYSICS**

A ball thrown horizontally with speed vi = 26.0m/s travels a horizontal distance of d = 60.0m before hitting the ground. From what height h was the ball thrown? Which I got this answer below. h= 26.1 m How do I solve for the one below. If it takes a ball dropped from rest 2....
*Thursday, February 5, 2015 at 6:26pm*

**physics**

A ferryboat is traveling north with a speed of 5.50 m/s relative to the water. A passenger is walking with a velocity of 2.50 m/s due east relative to the boat. What is the velocity (magnitude only) of the passenger with respect to the water?
*Thursday, February 5, 2015 at 6:24pm*

**physics**

The repulsive electric force between the point charges -6.36 * 10^-6 C and q has a magnitude of 1.32 N when the separation between the charges is 1.07 m. Find the sign and the magnitude of the charge q.
*Thursday, February 5, 2015 at 6:17pm*

**physics**

A particle carrying a charge of 6.0uC is located at the origin of a rectangle coordinate system, and a particle carrying a charge of 4.0uC is located at (0,5.0m). What are the magnitude and direction of the electric field at the positions (5.0m,0), (-5.0m,0), and (0,-5.0m)?
*Thursday, February 5, 2015 at 5:31pm*

**physics**

A positively charged solid sphere of radius 100 mm has a uniform volume charge density of 250 nC/m^2. Determine the electric field (a) 20 mm, (b) 90 mm, and (c) 110 mm from the center of the sphere.
*Thursday, February 5, 2015 at 5:30pm*

**physics**

A speeder passes a parked police car at a constant speed of 20.1 m/s. At that instant, the police car starts from rest with a uniform acceleration of 2.65 m/s How much time passes before the speeder is overtaken by the police car? Answer in units of s
*Thursday, February 5, 2015 at 4:44pm*

**physics**

A fire hose ejects a stream of water at an angle of 33.4 ° above the horizontal. The water leaves the nozzle with a speed of 20.1 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?
*Thursday, February 5, 2015 at 4:43pm*

**physics**

An arrow is shot straight upward into the air and it returns to the ground with a speed of 28m/s. What was the maximum height reached by the arrow?
*Thursday, February 5, 2015 at 2:00pm*

**physics**

A football is kicked at ground level with a speed of 17.9m/s at an angle of 36.0∘ to the horizontal. How much later does it hit the ground?
*Thursday, February 5, 2015 at 1:27pm*

**physics**

A ball thrown horizontally at 13.0m/s from the roof of a building lands 21.4m from the base of the building. How tall is the building?
*Thursday, February 5, 2015 at 1:22pm*

**physics**

As you walk to class with a constant speed of 1.65m/s , you are moving in a direction that is 18.8∘ north of east. How much time does it take to change your displacement by 21.0m east?
*Thursday, February 5, 2015 at 12:12pm*

**Physics**

A wheel on a moving car slows uniformly from 420 rpm to 120 rpm in 4 sec. A. What is the angular acceleration of the wheel? B. What is the angular displacement? How many revolutions? C. How far does the car travel if the radius of the wheel is 0.20cm?
*Thursday, February 5, 2015 at 10:23am*

**Physics**

A 0.25-kg punk, Initially at rest on a frictionless horizontal surface, is struck by a 0.20kg punk that is initially moving along the x-axis with a velocity of 2.20 m/sec. After the collision, the 0.20 kg punk has a speed of 1.5 m/s at an angle of 37 to the positive x-axis. ...
*Thursday, February 5, 2015 at 10:21am*

**physics**

A ball is released from a tower at a height of 100 meters toward the roof of another tower that is 25 meters high. The horizontal distance between the two towers is 20 meters. With what horizontal velocity should the ball be imparted so that it lands on the rooftop of the ...
*Thursday, February 5, 2015 at 9:58am*

**physics**

Three point charges are arranged along the x-axis. Charge q 1 = +3.00 ìC is at the origin, and charge q 2 = -5.00 ìC is at x = 0.200 m . Charge q 3 = +8.00 ìC . Where is q 3 located if the net force on q 1 is 7.00 N in the −x direction?
*Wednesday, February 4, 2015 at 10:29pm*