Sunday

July 24, 2016
**Physics**

A 910kg object is released from rest at an altitude of 1200 km above the north pole of the earth. If we ignore atmospheric friction, with what speed does the object strike the surface of the earth? (the polar radius of the earth is 6357 km)
*Sunday, March 6, 2016 by Anonymous*

**Physics**

An Alaskan rescue plane traveling 38 m/s drops a package of emergency rations from a height of 105 m to a stranded party of explorers. The acceleration of gravity is 9.8 m/s2. Where does the package strike the ground relative to the point directly below where it was released? ...
*Saturday, March 5, 2016 by Blake*

**physics**

What is the final equilibrium temperature when 40.0 grams of ice at 0°C is mixed with 5.00 grams of steam at 120°C? The specific heat of ice is 2.10 kJ/kg °C, the heat of fusion for ice at 0°C is 333.7 kJ/kg, the specific heat of water 4.186 kJ/kg °C, the ...
*Saturday, March 5, 2016 by athirah*

**physics**

At 20°C, a brass cube has an edge length of 34 cm. What is the increase in the cube's surface area when it is heated from 20°C to 67°C?
*Saturday, March 5, 2016 by Jim*

**Physics**

Does the total kinetic energy of an isolated system necessarily have to be conserved when its total momentum is conserved?
*Saturday, March 5, 2016 by Terry*

**Climate Physics**

Find the insolation in Wm^-2 at summer solstice for a low obliquity of 22 degrees? I used the following: h_0=cos^-1(-tan(phi)* tan(delta)) cos(theta)=[sin(phi)*sin(delta)+cos(phi)*cos(delta)*cos(h_0)] Result was 397 Wm^-2 This looked like an easy problem, but I am ...
*Saturday, March 5, 2016 by Alice*

**physics**

Force charges +q,-q,+q,-q placed at 4 corners of a square of sides 'a' calculate the resultant force on +Q charge at the intersection of 2 diagonals
*Saturday, March 5, 2016 by chandan*

**Physics**

If the sky diver releases her chute and an upward force of 800 Newtons is developed due to wind resistance, what will be the net force acting on her?
*Saturday, March 5, 2016 by Jamie*

**physics**

calculate the de-broglie wvelenth of the electron orbitting in the n=2 of hydrogen atom
*Saturday, March 5, 2016 by sajid*

**Physics **

An elastic cord can be stretched to its elastic limit by a load of 2N. If a 35cm length of the cord is extende 0.6cm by a force of the cord when the stretching force is 2.5N
*Saturday, March 5, 2016 by Cryptic *

**Physics**

A soccer ball of mass 550g is at rest on the ground. The soccer ball is kicked with a force of 108N. The player shoes is in contact with the ball for 0.3m. What is KE of the ball? What is the ball's velocity at the moment it loses contact with the soccer player's shoes?
*Saturday, March 5, 2016 by Sam*

**Physics**

A 55.3 kg skier is moving at 14.9 m/s on a frictionless horizontal, snow covered plateau when she encounters a rough patch 1.7 m long. The coefficient of kinetic friction between this patch and her skis is 0.27. After crossing the rough patch, what is the speed of the skier in...
*Saturday, March 5, 2016 by Desperate Student*

**physics**

A bicycle has 67.0 cm diameter wheels turning at 11.2 rev/s. How fast is the bicycle moving?
*Friday, March 4, 2016 by lizbeth*

**Physics 2 **

Two boxes are connected by a light string that passes over a light, frictionless pulley. One box rests on a frictionless ramp that rises at 30° above the horizontal (see the Figure below), and the system is released from rest. (a) Which way will the 50kg box move, up the ...
*Friday, March 4, 2016 by David*

**Physics**

Two boxes are connected by a light string that passes over a light, frictionless pulley. One box rests on a frictionless ramp that rises at 30° above the horizontal (see the Figure below), and the system is released from rest. (a) Which way will the 50kg box move, up the ...
*Friday, March 4, 2016 by David*

**physics**

A car in an amusement park travels without friction on a vertical loop of 20 m radius. Calculate from what minimum height h it needs to be released from rest in order to remain on the track at the top of the loop.
*Friday, March 4, 2016 by JuliePham*

**physics**

Two carts of masses m and 3m are at rest on a horizontal frictionless track. A person pushes each cart with the same force F for 5 s. If the kinetic energy of the lighter cart after the push is K = 180J, the kinetic energy of the heavier cart is :
*Friday, March 4, 2016 by JuliePham*

**Physics**

A crate is sliding down a ramp that is inclined at an angle 26.8 ° above the horizontal. The coefficient of kinetic friction between the crate and the ramp is 0.260. Find the acceleration of the moving crate.
*Friday, March 4, 2016 by Anonymous*

**Physics**

The near point of a patient's eye is 58.2 cm. (a) What should be the refractive power ℛ of a corrective lens prescribed to enable the patient to clearly see an object at 22.0 cm? ℛ = dpt (b) When using the new corrective glasses, the patient can see an object ...
*Friday, March 4, 2016 by Rahul*

**Physics**

A person can see an object in focus only if the object is no farther than 35 cm from the right eye and 58 cm from the left eye. Write a prescription for the refractive powers ℛ (in diopters) for the person's corrective lenses. right eye dpt left eye dpt
*Friday, March 4, 2016 by Rahul*

**Physics**

A slab of ice with parallel surfaces floats on water. What is the angle of refraction of a light ray in water if the light ray is incident on the upper ice surface with an angle of 60° to the normal?
*Friday, March 4, 2016 by Andrea*

**Physics**

A concave spherical mirror has a radius of curvature of 18 cm. Locate the images for object distances as given below. In each case, state whether the image is real or virtual and upright or inverted, and find the magnification. (If an answer does not exist, enter DNE. If an ...
*Friday, March 4, 2016 by Physics Lover*

**Physics**

A solid disk rotates in the horizontal plane at an angular velocity of 0.0684 rad/s with respect to an axis perpendicular to the disk at its center. The moment of inertia of the disk is 0.190 kg·m2. From above, sand is dropped straight down onto this rotating disk, so ...
*Thursday, March 3, 2016 by Anna*

**physics**

A long straight horizontal wire carries a current I = 4.80 A to the left. A positive 1.00 C charge moves to the right at a distance 5.00 m above the wire at constant speed v = 4500 m/s . What is the magnitude B of the magnetic field at the location of the charge due to the ...
*Thursday, March 3, 2016 by k*

**physics**

One of the conditions for Uniform Circular Motion is that the acceleration be centripetal and directed toward the center of motion. What would the effect be of a non-zero acceleration parallel to the tangential velocity?
*Thursday, March 3, 2016 by lizbeth*

**physics**

The front 1.20 m of a 1,350-kg car is designed as a "crumple zone" that collapses to absorb the shock of a collision. (a) If a car traveling 21.0 m/s stops uniformly in 1.20 m, how long does the collision last? s (b) What is the magnitude of the average force on the ...
*Thursday, March 3, 2016 by mark*

**physics**

A 3.30-kg steel ball strikes a massive wall at 10.0 m/s at an angle of θ = 60.0° with the plane of the wall. It bounces off the wall with the same speed and angle (see the figure below). If the ball is in contact with the wall for 0.204 s, what is the average force ...
*Thursday, March 3, 2016 by sara*

**physics**

A 0.224-kg volleyball approaches a player horizontally with a speed of 18.0 m/s. The player strikes the ball with her fist and causes the ball to move in the opposite direction with a speed of 22.0 m/s. (a) What impulse is delivered to the ball by the player? kg·m/s (b...
*Thursday, March 3, 2016 by sara*

**Physics **

A girl standing on a bridge throws a stone vertically downward with an initial velocity of 15.0 m/s into the river below. If the stone hit's the water 2.00 seconds later what is the height of the bridge above the water?
*Thursday, March 3, 2016 by Tyler *

**Physics M/C Quesion**

Two cyclists are travelling at constant speeds around a 400 m track in opposite direction. The speed of Jeff is 1.5 times the speed of Rob. The cyclists find they meet every 20 s. What is the speed of Jeff? A) 9.0 m/s B) 12 m/s C) 13 m/s D) 20 m/s E) 30 m/s
*Thursday, March 3, 2016 by the physics kid*

**Physics M/C Quesion**

A car travelling on a straight track accelerates uniformly from rest for 5.0 s and then travels at a constant speed for the next 5.0 s, covering a total distance of 75 m in that time. Determine the constant speed that the car achieved. A) 7.5 m/s B) 10 m/s C) 15 m/s D) 20 m/s ...
*Thursday, March 3, 2016 by The lost one *

**Physics**

An Alaskan rescue plane traveling 43 m/s drops a package of emergency rations from a height of 129 m to a stranded party of explorers. The acceleration of gravity is 9.8 m/s 2 . Where does the package strike the ground relative to the point directly below where it was released...
*Thursday, March 3, 2016 by Meghan*

**Physics**

Gold-198 with a half life of 2.6 days is used to diagnose and treat liver disease. Write a half life decay equation that relates the mass of au-198 remaining to time in days. What percentage of a sample of Au-198 would reamin after 1 day, 1 week? Given the information, I could...
*Thursday, March 3, 2016 by AlphaPrimes*

**Physics**

a box of mass 7 kg is pulled up a frictionless 30 degree incline by a force of 381 N which acts parallel to the incline surface. the box has an initial speed of 5m/s and is pulled 9m. what is the speed of the box at the end of the 9m.
*Thursday, March 3, 2016 by Anon*

**Physics**

Two soccer players, Mary and Jane, begin running from nearly the same point at the same time. Mary runs in an easterly direction at 4.43 m/s, while Jane takes off in a direction 60.2o north of east at 5.07 m/s. How long is it before they are 24.7 m apart? What is the velocity ...
*Thursday, March 3, 2016 by Ron*

**Physics**

a box of mass 7 kg is pulled up a frictionless 30 degree incline by a force of 381 N which acts parallel to the incline surface. the box has an initial speed of 5m/s and is pulled 9m. what is the speed of the box at the end of the 9m.
*Thursday, March 3, 2016 by S*

**Physics**

a mass, m = 2.1 kg, is ejected horizontally from a compressed coil with a force constant, k = 5.2 N/m and compression, x = 25 cm, onto a rough ramp that is 1.5 cm long with one end raised to a height, h= 120 cm. the speed at the bottom of the rough ramp is v=+3.037 m/s. the ...
*Thursday, March 3, 2016 by S*

**Physics**

a 2199 kg pile driver is used to drive a steel beam into the ground. the pile driver falls 8.8 m before contacting the beam, and it drives the beam 19 cm into the ground before coming to rest. using energy considerations, calculate the average force the beam exerts on the pile...
*Thursday, March 3, 2016 by Anonymous*

**Physics**

Imagine a landing craft approaching the surface of Callisto, one of Jupiter's moons. If the engine provides an upward force (thrust) of 2784 N, the craft descends at constant speed; if the engine provides only 1879 N, the craft accelerates downward at 0.39 m/s2. What is ...
*Thursday, March 3, 2016 by Kameron*

**Physics**

A car traveling at 71 km/h hits a bridge abutment. A passenger in the car moves forward a distance of 63 cm (with respect to the road) while being brought to rest by an inflated air bag. What magnitude of force (assumed constant) acts on the passenger's upper torso, which...
*Thursday, March 3, 2016 by Kaley*

**physics**

A block of mass m = 5.90 kg is released from rest from point circled A and slides on the frictionless track shown in the figure below. (Assume ha = 7.30 m.) point b is 3.20 m and point c is 2.00m. (a) Determine the block's speed at points circled B and circled C. point ...
*Thursday, March 3, 2016 by mark*

**physics**

ball of mass m = 1.70 kg is released from rest at a height h = 54.0 cm above a light vertical spring of force constant k. The ball strikes the top of the spring and compresses it a distance d = 8.80 cm Neglecting any energy losses during the collision, find the following. a) ...
*Thursday, March 3, 2016 by sherry*

**physics**

An older-model car accelerates from 0 to speed v in 10. s. A newer, more powerful sports car of the same mass accelerates from 0 to 4v in the same time period. Assuming the energy coming from the engine appears only as kinetic energy of the cars, compare the power of the two ...
*Thursday, March 3, 2016 by sherry*

**physics**

An archer pulls her bowstring back 0.420 m by exerting a force that increases uniformly from zero to 240 N. (a) What is the equivalent spring constant of the bow? N/m (b) How much work does the archer do in pulling the bow? J
*Thursday, March 3, 2016 by sherry*

**physics**

A 0.290-kg block along a horizontal track has a speed of 1.30 m/s immediately before colliding with a light spring of force constant 53.4 N/m located at the end of the track. (a) What is the spring's maximum compression if the track is frictionless? m
*Thursday, March 3, 2016 by sherry*

**Physics**

A circuit consists of a 10 ohm resistor in series with 3 identical batteries each with an emf = 1.0V and internal resistance of 5 ohms. a) find potential difference between the terminals b) potential difference across the 10 ohm resistor c) power dissipated in resistor
*Thursday, March 3, 2016 by Joe*

**PHYSICS HELP**

Determine the normal force for a laundry basket with a mass of 4.5 kg in each of the following situations (a) at rest on a horizontal surface? __ n (b) at rest on a ramp inclined at 12° above the horizontal? __N (c) at rest on a ramp inclined at 25° above the ...
*Thursday, March 3, 2016 by Cheyenne*

**Physics**

An electric field with constant magnitude and direction is said to be?
*Thursday, March 3, 2016 by MeritGodwin*

**Physics**

Determine the acceleration of an electron placed in a constant downward electric field of 4.0X10^5N/C.
*Thursday, March 3, 2016 by MeritGodwin*

**Physics**

Object Y is attracted to object B. If object B is known to be positively, what can we say about object A
*Thursday, March 3, 2016 by MeritGodwin*

**physics**

An egg is thrown nearly vertically upward from a point near the cornice of a tall building. It just misses the cornice on the way down and passes a point 8.5 m below its starting point 3.0 s after it leaves the thrower’s hand. Air resistance may be ignored. (c) What is ...
*Thursday, March 3, 2016 by kane*

**Physics**

The equation of a transverse wave travelling wave on a string is: Y=3 cos[3.14(0.5x-200t)] Where x and y in cm and t is in second. a)find the amplitude, wave length,frequency period,velocity of propagation. b)if the mass per unit length of the string is 0.5 kg/m find the tension.
*Thursday, March 3, 2016 by Megha*

**physics**

A 60ft aluminum at 60 degree farenhiet to 100 degree farenhiet. Whats is the final length of the aluminum?
*Thursday, March 3, 2016 by marvin*

**Physics 101**

Two ice skaters, each with a mass of 72.0 kg, are skating at 5.10 m/s when they collide and stick together. If the angle between their initial directions was 117°, determine the components of their combined velocity after the collision. (Let the initial motion of skater 1 ...
*Thursday, March 3, 2016 by Lorelei*

**physics**

In a series L.C.circuit the inductant and capacitant are 0.5H and 20mf respectively. calculate the resonance frequency of the circuit.
*Wednesday, March 2, 2016 by Blue*

**physics**

A car moves 3 kph. Car B which is 50 m ahead of Car A is moving at 6 kph. If car A accelerates by 5m/s/s, determine if the cars will collide.
*Wednesday, March 2, 2016 by Hannah*

**Physics**

A waterfall is 1260m high. calculate the change in temperature of the quantity of water that falls from the top to the bottom of the waterfall( neglect heat losses to the surrounding) take g to be 10m/s and specific.heat capacity of water to be 4200j/kg/k.
*Wednesday, March 2, 2016 by Blue*

**Physics**

A string under a tension of 43.0 N is used to whirl a rock in a horizontal circle of radius 2.25 m at a speed of 20.0 m/s on a frictionless surface as shown in the figure below. As the string is pulled in, the speed of the rock increases. When the string on the table is 1.00 m...
*Wednesday, March 2, 2016 by Jack*

**physics**

A string under a tension of 43.0 N is used to whirl a rock in a horizontal circle of radius 2.25 m at a speed of 20.0 m/s on a frictionless surface as shown in the figure below. As the string is pulled in, the speed of the rock increases. When the string on the table is 1.00 m...
*Wednesday, March 2, 2016 by Kevin*

**Physics**

What is the velocity of the simple harmonic motion problem? Position of the graph is y= .4*cos(2pi*1/3*x)+1.2 I need to find the velocity as well as the acceleration. I have worked through it and keep getting that the velocity is 0. I don't believe that is correct.
*Wednesday, March 2, 2016 by Dib*

**Physics **

1.) jet plane traveling 1800 km/h (500 m/s) pulls out of a dive by moving in an arc of radius 6.00 km. What is the plane's acceleration in g's? 6.) A child on a merry -go-round is moving with a speed of 1.35 m/s when 1.20 m from the center of the merry-go-round. a.) ...
*Wednesday, March 2, 2016 by JT*

**Physics**

3/2/2016 An unknown substance at a temperature of 20 degrees Celsius is warmed up to 50 degrees when water at 80 degrees is added to it. The sum of the masses of the unknown substance and water is equal to 1000grams. In another experiment, the same substance at 20 degrees is ...
*Wednesday, March 2, 2016 by Marilynn on behalf of Victor Hopman*

**Physics**

A machine has an overcome of 60percent.If the machine is required to overcome a load of 30N with a force 20N.calculate it velocity ratio?
*Wednesday, March 2, 2016 by Dalong*

**PHYSICS**

Yuvi is trying out for the track & field team and wants to give long jump a try. He currently can reach a distance of 5.90 m when leaving the ground at an angle of 30.0°. (a) What is his takeoff speed? (b) If Yuvi could increase his takeoff speed 5.0%, how much further ...
*Wednesday, March 2, 2016 by Rob*

**Physics**

A hostess wants to cool her 100g of soup which is currently at 50Celsius, and it's specific heat is 0.8 cal/g celsius, by adding water (specific heat = 1 cal/ g celsius) at a temperature of 5Celsius, how much water should she add, assuming that all the heat from the soup ...
*Wednesday, March 2, 2016 by Mad*

**physics **

determine the thrust produced if 1.5 x 10^3 kg of gas exits the combustion chamber each second, with a speed of 4.00 x 10^3 m/s
*Wednesday, March 2, 2016 by john*

**Physics **

The system of nine small 3 kg objects is rotating at an angular speed of 6 rev/s. The objects are connected by light, flexible spokes that can be lengthened or shortened. What is the new angular speed if the spokes are shortened from 6 m to 2 m?
*Wednesday, March 2, 2016 by Anonymous*

**physics**

how many electrons drift past a point on for 10 minutes current is 0.2 A.the charge on one electrons 1.6*10^-1
*Wednesday, March 2, 2016 by ruth*

**physics**

A 5.3-kg block is pushed 2.3 m up a vertical wall with constant speed by a constant force of magnitude F applied at an angle of θ = 30° with the horizontal, as shown in the figure below. If the coefficient of kinetic friction between block and wall is 0.30, determine ...
*Wednesday, March 2, 2016 by sherry*

**physics**

1)a galvanometer has a resistance of 40 ohm and is of 3 mA full-scale deflection.how would you modify it to act as a 0-5 A ammeter? 2)the galvanometer described in question 1 is to be converted into a 0-5 V voltmeter. a)when the voltmeter is connected to a 5 V supply ,how ...
*Wednesday, March 2, 2016 by ruth*

**Physics**

A 2.92 kg block starts from rest at the top of a 30° incline and accelerates uniformly down the incline, moving 1.93 m in 1.60 s. (a) Find the magnitude of the acceleration of the block. __ m/s2 (b) Find the coefficient of kinetic friction between the block and the incline...
*Wednesday, March 2, 2016 by Cheyenne*

**Physics**

Determine the normal force for a laundry basket with a mass of 4.5 kg in each of the following situations... (a) at rest on a horizontal surface? ___ N (b) at rest on a ramp inclined at 12° above the horizontal? ___ N (c) at rest on a ramp inclined at 25° above the ...
*Wednesday, March 2, 2016 by Cheyenne*

**Physics**

Yuvi is trying out for the track & field team and wants to give long jump a try. He currently can reach a distance of 5.90 m when leaving the ground at an angle of 30.0°. (a) What is his takeoff speed? (b) If Yuvi could increase his takeoff speed 5.0%, how much further ...
*Wednesday, March 2, 2016 by Rob*

**Physics**

An ice skater of mass (on frictionless ice) fires a bullet of mass 10 grams that leaves the barrel at 500 m/s (in the x-direction relative to the ground) A) what is the recoil velocity of the skater relative to the ground? B) how much work is done in the bullet by the ...
*Wednesday, March 2, 2016 by Fullmetal *

**physics**

the current in alightning strike is 7500A.the strike lasts for 240ms.calculate a,the charge in c ,which flows in the strike to the ground b,the number of electrons transferred to the ground
*Wednesday, March 2, 2016 by suzy*

**Physics**

A 60kg man standing on a stationary 40kg boat throws a 0.2kg ball with a velocity of m/s. Assuming there is no friction between the man and the boat, what is the speed of the boat after the man throws the ball?
*Wednesday, March 2, 2016 by Sami*

**Physics **

Calculate the force required to pull a copper ball of radius 2.00 cm upward through a fluid at the constant speed 6.00 cm/s. Take the drag force to be proportional to the speed, with proportionality constant 0.950 kg/s. Ignore the buoyant force. N
*Tuesday, March 1, 2016 by Kev*

**Physics**

1. A car undergoes a displacement of 500m due east, followed by another displacement due south of 1200m. a)Calculate the total distance traversed by the car d1+d2=total distance 500+1200=1700m b) Calculate the total displacement of the car D=√(500^2+1200^2)=1300 tan^-1(...
*Tuesday, March 1, 2016 by Steve *

**Physics**

Block B in the figure weighs 739 N. The coefficient of static friction between block and table is 0.34; angle θ is 26°; assume that the cord between B and the knot is horizontal. Find the maximum weight of block A for which the system will be stationary.
*Tuesday, March 1, 2016 by Daisy*

**physics**

Boxes A and B are connected to each end of a light vertical rope. A constant upward force F = 80.0 N is applied to box A. Starting from rest, box B descends 12.0 m in 4.00 s. The tension in the rope connecting the two boxes is 36.0 N. What are the masses of (a) box B, (b) box A?
*Tuesday, March 1, 2016 by Kayla*

**Physics**

I was wondering if you could clarify this question. How much thermal energy is needed to change 100 g of ice at -20 degrees celsius into steam at 110 degrees celsius? Q = mLv (Lv = Specific latent heat of vapourization) I can't find the Lv for ice. Is this a two step ...
*Tuesday, March 1, 2016 by JavaUtility*

**Physics**

How much thermal energy is released when 500 g of steam at 100 degrees celsius condenses into liquid and then cools to 50 degrees celsius. What I`ve Attempted: Q=mLv m = 500g (0.5 kg) Lv = 2.3*10^6 Q=(0.5)(2.3*10^6) Q=1,150,000 J Q = 1.2*10^6 The answer in the back of the book...
*Tuesday, March 1, 2016 by AlphaStrike*

**physics**

Your CECS graduation tassel hangs from the rear view mirror of your graduation gift, a 1981 DeLorean DMC-12 with Mr. Fusion garbage fusion generator!!! Your tassel hangs plumb or vertical when driving at a constant speed on a level highway. When accelerating you observe the ...
*Tuesday, March 1, 2016 by Jesse*

**Physics**

What is the velocity of the simple harmonic motion problem? Position of the graph is y= .4*cos(2pi*1/3*x)+1.2 I need to find the velocity as well as the acceleration. I have worked through it and keep getting that the velocity is 0. I don't believe that is correct.
*Tuesday, March 1, 2016 by Dib*

**physics**

The figure here shows four penguins that are being playfully pulled along very slippery (frictionless) ice by a curator. The masses of three penguins and the tension in two of the cords are m1 = 12 kg, m3 = 16 kg, m4 = 21 kg, T2 = 101 N, and T4 = 202 N. Find the penguin mass ...
*Tuesday, March 1, 2016 by sara*

**physics**

You live at the top of a steep (a slope of ???? degrees above the horizontal) hill and must park your 2200 kg car on the street at night. a) You unwisely leave your car out of gear one night and your handbrake fails. Assuming no significant frictional forces are acting on the ...
*Tuesday, March 1, 2016 by sabrina*

**physics**

A 5.25-kg ball, moving to the right at a velocity of +2.10 m/s on a frictionless table, collides head-on with a stationary 7.60-kg ball. Find the final velocities of the balls if the collision meet the following conditions. (a) elastic 5.25-kg ball = Incorrect: Your answer is ...
*Tuesday, March 1, 2016 by Rhea *

**PHYSICS**

a student consumed a 0.23 kg of juice with 115 calories per 1.15 serving. How much work you must perform to remove these calories?
*Tuesday, March 1, 2016 by HANNAH*

**physics**

A mettalic sphere of radius a carries a charge Q. It is brought in contact with an uncharged sphere of radius b . what will be the charge on the first sphere. My work I eliminated 2 options by substitution and realised that it won't be their average as they don't have ...
*Tuesday, March 1, 2016 by Anonymous*

**science (physics)**

A copper wire with cross sectional area 0.00030cm^2 is to be used in lifting a 100g object.How fast can the object be accelerated if the wire is to stretch not more than 0.10%? What i know is that first find the elongation & then that will help to find acceleration..
*Tuesday, March 1, 2016 by joan*

**physics**

A 1.5 kg book is lying on a 0.70 m -high table. You pick it up and place it on a bookshelf 2.0 m above the floor. During this process, how much work does gravity do on the book? -> 1.5 * -9.8 * 1.3 = -19.1 J During this process, how much work does your hand do on the book?
*Tuesday, March 1, 2016 by Anonymous*

**Physics**

You are on vacation in San Francisco and decide to take a cable car to see the city. A 5500 kg cable car goes 360 m up a hill inclined 19 ∘ above the horizontal. What can your learn about the work done by the cable to move car up the hill? Answer quantitatively. Ignore ...
*Monday, February 29, 2016 by James*

**Science (Physics)**

Air becomes a conductor when the electric field strength exceeds 3.00 × 106 N/C. Determine the maximum amount of charge that can be carried by a metal sphere 8.5 m in radius. The value of the Coulomb constant is8.99×109 N·m2/C2. Answer in units of C. I have ...
*Monday, February 29, 2016 by Lydia*

**physics**

Question: You live at the top of a steep (a slope of ???? degrees above the horizontal) hill and must park your 2200 kg car on the street at night. a) You unwisely leave your car out of gear one night and your handbrake fails. Assuming no significant frictional forces are ...
*Monday, February 29, 2016 by tom*

**Physics**

Rosie (mass 41 kg) pushes a box with a horizontal force of 140 N (31.472 lb) at a speed 25 m/min. A. What is Rosie’s power output? Answer in units of W. B.What energy is produced by a 300 W lightbulb lit for 4.1 hours? Answer in units of J
*Monday, February 29, 2016 by Sam*

**Physics**

Zak, helping his mother rearrange the furniture in their living room, moves a 42.3 kg sofa 7.2 m with a constant force of 17 N. A. What is the work done by Zak on the sofa? Neglect friction. Answer in units of J. B. What is the average acceleration of the sofa? Answer in units...
*Monday, February 29, 2016 by Sam*

**Physics **

Block A is 4.5 kg and Block B is 2.25 kg. a. determine the mass of block C that must be placed on block A to keep it from sliding if the coefficient of static friction between block A and the table is 0.2 b. If the coefficient of kinematic friction between the surface and ...
*Monday, February 29, 2016 by Diana*

**physics **

A 5 kg block is being held against the wall. What is the minimum force needed to keep the block from moving if the force is applied at an angle that is 15 degrees above the horizontal. The coefficient of static friction between the wall and the block is 0.275.
*Monday, February 29, 2016 by Jamie*

**Physics**

Please check my answers!! 1. A 75 kg. man steps off the end of a diving board, and hits the water at 7.7 m/s. Ignoring air resistance, what was the mans PE (potential energy) right before he stepped off the diving board? I got 2223.375 Joules after Damon helped me...am I right...
*Monday, February 29, 2016 by Becca*

**Physics**

1. A box is placed on the end of a 3 meter plank. One end of the plank is gradually raised and it is observed that the box begins to slide when the board reaches an angle of 25 degrees. a. Determine how long the box will take to reach the end of the plank if the coefficient of...
*Monday, February 29, 2016 by Daniel*