Tuesday

March 31, 2015

March 31, 2015

**Recent Homework Questions About Physics**

Post a New Question | Current Questions

**Physics**

Two horizontal forces Upper F1 Baseline and F2 act on a 3.6 kg disk that slides over frictionless ice, on which an xy coordinate system is laid out. Force F1 is in the positive x direction and has a magnitude of 7.1 N. Force F2 has a magnitude of 9.3 N. The figure here gives ...
*Sunday, March 15, 2015 at 10:06am*

**physics**

The system is frictionless and the trolley accelerates to the left at 3m/s squared. (a) calculate the unknown mass M. (b) calculate the magnitude of the forces in each string.
*Sunday, March 15, 2015 at 10:01am*

**physics 10**

1.) 100 kJ of heat is added to 600g of zinc at 20 C and 75g of it melts. If the specific heat of zinc is 0.385 kJ/kg-C and it melts at 420 C. What is its heat of fusion? 2.) If all the heat lost by 1kg of water at 0 C when it turns into ice at 0 C could be burn into KE, What ...
*Sunday, March 15, 2015 at 4:32am*

**PHYSICS**

The gravitational forces of the Earth and the Moon are attractive, so there must be a point on a line joining their centers where the gravitational forces on an object cancel. How far is this distance from the Earth's center?
*Sunday, March 15, 2015 at 2:59am*

**physics**

A 55 grams copper calorimeter contains an unknown mass of water at 18 degrees celcius. When 755 grams of alloy at 100 degrees celcius is dropped into the calorimeter ,the resulting temperature is 20.4 degrees celcius. Determine the mass of water.
*Sunday, March 15, 2015 at 12:11am*

**Physics**

You have a solution that contains Ca2+ ions and another that contains Na+ ions. How would adding a solution that contains CO2-3 ions enable you to tell which is which?
*Sunday, March 15, 2015 at 12:09am*

**physics**

when 200 grams of aluminum at 100 degrees celsius is dropped into an aluminum calorimeter of mass 120 grams and containing 150 grams of kerosene at 15 degrees celsius,the mixtures reaches a temperature of 50 degrees celsius.what is the specific heat of kerosene?
*Saturday, March 14, 2015 at 11:33pm*

**Physics**

Assuming atmospheric pressure to be 1.01 x 10^5 Pa and the density of sea water to be 1025 kg/m^3, what is the absolute pressure at a depth of 15.0m below the surface of the ocean? Could you show me how to do this problem? Thank you.
*Saturday, March 14, 2015 at 9:36pm*

**Physics **

1. What is the kinetic energy of a 0.50 g insect traveling in a straight line at 5.0m/s? a. 6.25j b. 1.25j c. 5.0j d. 250j Is the answer A?? 2. Mechanical energy is defined as the sum of which of the following? a. kinetic, potential and radiant energy b. kinetic, potential and...
*Saturday, March 14, 2015 at 9:28pm*

**Physics**

A 1.42 kg ball is connected by means of two massless strings, each of length L = 1.29 m, to a vertical, rotating rod. The strings are tied to the rod with separation d = 1.29 m and are taut. The tension in the upper string is 48.0 N. What are (a) the tension in the lower ...
*Saturday, March 14, 2015 at 4:52pm*

**physics**

A 130-kg crate is initially at rest on a horizontal frictionless surface. An applied force of 400 N to the right is exerted on the crate, causing it to move and cover a distance of 26.0 m. At the end of its path, the crate is found to be moving at a speed of 15.0 m/s. (a) What...
*Saturday, March 14, 2015 at 9:18am*

**Physics**

Hi, can anybody provide some hints in how to approach these questions? I've been stuck on it for days!!! Thank you in advance!! Nodes of a Standing Wave: Consider a standing wave, where y represents the transverse displacement of a string that extends along the x direction...
*Saturday, March 14, 2015 at 5:59am*

**physics**

The density of copper is 8930 kg per cubic metre. A rod of copper is 20 cm long. What length of it will remain immersed in mercury of density 13600 kg per cubic metre
*Saturday, March 14, 2015 at 5:44am*

**physics**

A chair of mass 14.0kg is sitting on the horizontal floor; the floor is not frictionless. You push on the chair with a force F = 40.0N that is directed at an angle of 43.0∘ below the horizontal and the chair slides along the floor.
*Saturday, March 14, 2015 at 5:01am*

**physics**

a car is moving at speed of 50km/hr ,can be stopped by brake at least at 6 m.If the same car is moving at speed of 100 km/hr ,what is the minimum stopping distance?
*Saturday, March 14, 2015 at 3:58am*

**Physics - Mechanics**

A small block of mass 1.2 kg is launched by a compressed spring with force constant k=600 N/m. The initial compression of the spring is 0.15 m. The block slides along a horizontal frictionless surface and then up an inclined plane that makes an angle θ=40˚ with the ...
*Saturday, March 14, 2015 at 2:35am*

**Physics - Mechanics**

A large box of mass M is at rest on a horizontal table whose surface is rough; the coefficient of static friction between the table and the block is μ. The box is connected by a taut string to a small block of unknown mass m, initially held horizontally as shown and then ...
*Saturday, March 14, 2015 at 2:34am*

**Physics - Mechanics**

A bullet of mass m is shot at speed v toward a pendulum bob of mass M. The bullet penetrates through the block and emerges on the other side traveling at speed v/2. 1. What is the speed v_block of the block immediately after the bullet emerges from the block (In terms of M, m ...
*Saturday, March 14, 2015 at 2:33am*

**Physics**

two cars start from rest and begin accerlating, one at 10m/s^2 and the other at 12m/s^2. how long will it take for the second car to be 100m ahead of the first car
*Friday, March 13, 2015 at 11:44pm*

**Physics**

A beam of light makes an angle of θi = 53.0˚ with the normal of a slab of transparent material of t=3.80 mm-thickness. The index of refraction of the glass is n2 = 1.39. Angle 3 is 53.1 b) How far vertically (d) is the point at which the beam leaves the glass surface...
*Friday, March 13, 2015 at 8:55pm*

**physics(Please respond)**

if a rock is dropped into a well and it takes 17 seconds to hit the water how far down is the water level from the top of the well
*Friday, March 13, 2015 at 8:43pm*

**college physics**

When a thin 12.0cm iron rod moves with a constant velocity of 6.50m/s perpendicular to the rod, the induced emf across its ends is measured to be 0.300V. What is the magnitude of the magnetic field?
*Friday, March 13, 2015 at 5:52pm*

**Physics**

In the drawing, the weight of the block on th e table is 380 N and that of the hanging block is 175 N. Ignore all frictional effects, and assuming the pulley to be massless. What is the acceleration of the two block?
*Friday, March 13, 2015 at 3:13pm*

**physics**

If you do 500J of work to elevate a bucket of water, what is its gravitational potential energy relative to its starting position? 500*10=5,000 5,000/500=10
*Friday, March 13, 2015 at 11:15am*

**PHYSICS**

A submarine is trapped at the bottom of the ocean with its hatch at a depth of 20 m below the surface. The hatch is circular and 0.40 m. Calculate the force that would have to be exerted against it to open it. The air inside the submarine has a pressure of 1 Atm. -I used P=f/a...
*Friday, March 13, 2015 at 11:14am*

**Physics - Mechanics**

A small block of mass 1.2 kg is launched by a compressed spring with force constant k=600 N/m. The initial compression of the spring is 0.15 m. The block slides along a horizontal frictionless surface and then up an inclined plane that makes an angle θ=40˚ with the ...
*Friday, March 13, 2015 at 10:24am*

**Physics - Mechanics**

A large box of mass M is at rest on a horizontal table whose surface is rough; the coefficient of static friction between the table and the block is μ. The box is connected by a taut string to a small block of unknown mass m, initially held horizontally as shown and then ...
*Friday, March 13, 2015 at 10:22am*

**Physics - Mechanics**

A bullet of mass m is shot at speed v toward a pendulum bob of mass M. The bullet penetrates through the block and emerges on the other side traveling at speed v/2. 1. What is the speed v_block of the block immediately after the bullet emerges from the block (In terms of M, m ...
*Friday, March 13, 2015 at 10:14am*

**Physics**

A hollow spherical shell with mass 2.45kg rolls without slipping down a slope that makes an angle of 30.0∘ with the horizontal. a.) find the magnitude of the acceleration of the center of mass of the spherical shell. b.) find the magnitude of the frictional force acting ...
*Friday, March 13, 2015 at 1:03am*

**Physics**

A mass of 5Kg is 1st weighed on a balance at the top of a tower 20m high.The man is then suspended from a fine wire 20m long and reweivhed.find the difference in a weight ,assuming that the radius of the earth is 6400km,the mass of the earth is 6×10^24kg and G=6.673&...
*Friday, March 13, 2015 at 12:57am*

**physics**

A projectile of mass 0.803 kg is shot straight up with an initial speed of 24.8 m/s. (a) How high would it go if there were no air resistance? (b) If the projectile rises to a maximum height of only 9.36 m, determine the magnitude of the average force due to air resistance
*Thursday, March 12, 2015 at 11:45pm*

**Physics**

A hollow spherical shell with mass 2.45kg rolls without slipping down a slope that makes an angle of 30.0∘ with the horizontal. a.) find the magnitude of the acceleration of the center of mass of the spherical shell. b.) find the magnitude of the frictional force acting ...
*Thursday, March 12, 2015 at 11:37pm*

**Physics**

what is the mass of the toy truck if the force of friction holding it in place is 18.5N u= 0.2 at 30 degrees
*Thursday, March 12, 2015 at 8:35pm*

**Physics**

A hollow spherical shell with mass 2.45kg rolls without slipping down a slope that makes an angle of 30.0∘ with the horizontal. a.) find the magnitude of the acceleration of the center of mass of the spherical shell. b.) find the magnitude of the frictional force acting ...
*Thursday, March 12, 2015 at 6:26pm*

**Physics**

A 2.0 lb block is given an initial speed of 4.0 ft/sec up an inclined plane starting from a point 2.0 feet from the bottom as measured along the plane. If the plane makes an angle (theta = 30 degrees) with the horizontal and the coefficient of friction is 0.20, how far up the ...
*Thursday, March 12, 2015 at 5:13pm*

**Physics**

A small wooden block with mass 0.800kg is suspended from the lower end of a light cord that is 1.52m long. The block is initially at rest. A bullet with mass 0.0126kg is fired at the block with a horizontal velocity v0. The bullet strikes the block and becomes embedded in it. ...
*Thursday, March 12, 2015 at 4:56pm*

**Physics**

At New York City, the earth's magnetic field has a vertical component of that points downward (perpendicular to the ground) and a horizontal component of that points toward geographic north (parallel to the ground). What are the magnitude and direction of the magnetic ...
*Thursday, March 12, 2015 at 3:03pm*

**Physics**

A 100 lb block of ice slides down an incline 5.0 ft long and 3.0 ft high. A worker pushes up on the ice parallel to the incline so that it slides down at constant speed. The coefficient of friction between the ice and the incline is 0.10. Find (a) the force exerted by the ...
*Thursday, March 12, 2015 at 1:33pm*

**Physics**

What kind (s) of particles make up (a) gaseous compounds, (b) liquid compounds, and (c) solid compounds?
*Thursday, March 12, 2015 at 1:06pm*

**physics**

How do I: a.) find the energy in a 3.50x10^-5f parallel plate capacitor if it holds 2.00x10^-3c of charge b.)find the voltage between the plates c.)determine the new voltage after doubling the stored energy
*Thursday, March 12, 2015 at 12:58pm*

**physics **

The heaviest invertebrate is the giant squid, which is estimated to have a weight of about 0.35 tons spread out over its length of 38 feet. What is its weight in newtons?
*Thursday, March 12, 2015 at 11:56am*

**Physics**

Assume you have a rocket that requires a change in velocity of DeltaV=9.6km/s . There are two options for the propulsion system --- 1. chemical and 2. electric --- each with a different specific impulse. Using the setting of g0 =9.81m/s^2 to calculate the propellant fraction ...
*Thursday, March 12, 2015 at 11:27am*

**Physics **

Assume you have a rocket that requires a change in velocity of ¦¤V¡Ö9.6km/s . There are two options for the propulsion system --- 1. chemical and 2. electric --- each with a different specific impulse. Using the setting of g 0 =9.81m/s^2 to calculate ...
*Thursday, March 12, 2015 at 11:22am*

**Physics**

What is the centripetal acceleration in meters per second squared of a point on the rim of a circle with a radius of 0.45 meters and turning at a rate of 1200 rpm?
*Thursday, March 12, 2015 at 10:22am*

**Physics**

A diver running 1.8 m/s dives out horizontally from the edge of the cliff and 3 s later he reaches the water below. (a) Calculate the resultant velocity (with direction) of the diver just before he hits the water. (10) (b) How high is the cliff, and how far from its base did ...
*Thursday, March 12, 2015 at 8:55am*

**Physics**

A body of mass m is suspended from a spring with spring constant k and the spring is stretched 0.1. If two identical bodies of mass m/2 are suspended from a spring with the same spring constant k, how much will the spring stretch? Explain your answer. The first case is when ...
*Thursday, March 12, 2015 at 4:44am*

**Physics**

There is a band who uses 10000 W to radiate sound energy in all directions. What was the intensity of sound 10 meters from this speaker? What was the sound level in dB at a distance of 10 m? At what distance from the speaker was the sound level 100 dB?
*Thursday, March 12, 2015 at 12:40am*

**Physics**

The distance between two consecutive nodes of a standing wave is 19.2 cm. The hand generating the pulses moves up and down through a complete cycle 2.59 times every 7.44 s. Find the velocity of the wave. Answer in units of m/s.
*Wednesday, March 11, 2015 at 10:53pm*

**Physics**

What is the volume of water at 95 degrees Celcius if at 5 degrees Celcius the water is 5.56L?
*Wednesday, March 11, 2015 at 10:13pm*

**Physics**

A 100 lb block of ice slides down an incline 5.0 ft long and 3.0 ft high. A worker pushes up on the ice parallel to the incline so that it slides down at constant speed. The coefficient of friction between the ice and the incline is 0.10. Find (a) the force exerted by the ...
*Wednesday, March 11, 2015 at 10:10pm*

**Physics**

A raft measures 1.7m x 0.67m x 0.14m, and it has a mass of 13.5kg. What is the maximum mass that the raft can hold and still stay afloat
*Wednesday, March 11, 2015 at 10:08pm*

**physics**

a train stopping distance, even when full emergency brakes are engaged, is 1.3 km. if the train was travelling at an initial velocity of 90 km/h [forward], determine its acceleration under full emergency brakes.
*Wednesday, March 11, 2015 at 7:37pm*

**physics**

A light beam in air enters a block of transparent material at an angle of 28.0˚ with respect to the normal. After refraction it makes an angle of 19.0˚ with respect to the normal. a) Find the index of refraction of the material. b) In a second setting, the light ...
*Wednesday, March 11, 2015 at 7:10pm*

**physics**

A 2.40 kg mess kit sliding on a frictionless surface explodes into two 1.20 kg parts: 3.78 m/s, due north, and 5.28 m/s, 32.8° north of east. What is the original speed of the mess kit?
*Wednesday, March 11, 2015 at 6:55pm*

**Physics**

A 75kg firefighter slides down a 2.5m fire pole from rest. It takes the firefighter 1.8s to reach the ground. If the firefighter bends his knees when he reaches the ground such that his centre of mass mives 41cm while coming to a stop, what must the normal force of the ground ...
*Wednesday, March 11, 2015 at 6:29pm*

**Ap physics**

Rotational Motion/Torque The question says that "A 60.0kg painter is on a uniform 25 kg scaffold supported from above by ropes. There is a 5.0 kg pail of paint to one side, as shown. How far from the left end of the scaffold should the painter stand such that the right ...
*Wednesday, March 11, 2015 at 6:16pm*

**Physics**

A pilot wants to fly directly north to an airport 500 km away. His speed relative to the air is 100 km/h. Howevere there is a 40 km/h cross wind blowing from west to east. At what angle relative to the south north direction should he fly to arrive at the distant airport? How ...
*Wednesday, March 11, 2015 at 6:03pm*

**Physics**

A 75kg firefighter slides down a 2.5m fire pole from rest. It takes the firefighter 1.8s to reach the ground. If the firefighter bends his knees when he reaches the ground such that his centre of mass mives 41cm while coming to a stop, what must the normal force of the ground ...
*Wednesday, March 11, 2015 at 5:08pm*

**Physics**

A 75kg firefighter slides down a 2.5m fire pole from rest. It takes the firefighter 1.8s to reach the ground. If the firefighter bends his knees when he reaches the ground such that his centre of mass mives 41cm while coming to a stop, what must the normal force of the ground ...
*Wednesday, March 11, 2015 at 5:06pm*

**Physics**

A 100 lb block of ice slides down an incline 5.0 ft long and 3.0 ft high. A worker pushes up on the ice parallel to the incline so that it slides down at constant speed. The coefficient of friction between the ice and the incline is 0.10. Find (a) the force exerted by the ...
*Wednesday, March 11, 2015 at 4:36pm*

**physics**

The angular position of a flywheel is given by theta=(2+5t+2t^2)rad . find the angular speed and acceleration at 3^rd second after the motion had been started.
*Wednesday, March 11, 2015 at 3:09pm*

**physics**

2) Two objects are initially the same height above the ground. Simultaneously, one is released from rest and the other is shot horizontally with an initial speed of 2.5 m/s. The two objects collide after falling 20.0 m. How far apart were the objects initially?
*Wednesday, March 11, 2015 at 2:50pm*

**physics**

2)Two objects are initially the same height above the ground. Simultaneously, one is released from rest and the other is shot horizontally with an initial speed of 2.5 m/s. The two objects collide after falling 20.0 m. How far apart were the objects initially?
*Wednesday, March 11, 2015 at 2:45pm*

**physics**

two blocks of each mass m=3.75kg are fastened to the ceiling of an elevator. If the elevator accelerates upward at 1.6m/s^2. Find the tension in T1 and T2 in each upper and lower rope
*Wednesday, March 11, 2015 at 1:42pm*

**Physics**

A mover pushes a 60 lb box 30 ft along a level floor at constant speed with a force directed 45 degrees below the horizontal. If the coefficient of kinetic friction is 0.20, how much work does the mover do on the box? ...Is this one of those trick questions where the work is 0?
*Wednesday, March 11, 2015 at 11:00am*

**physics**

a force of 10N acts on an object and raises its speed from 0 to 5 m/s in 10s.calcuate the average power.
*Wednesday, March 11, 2015 at 7:50am*

**Physics**

A 100 lb block of ice slides down an incline 5.0 ft long and 3.0 ft high. A worker pushes up on the ice parallel to the incline so that it slides down at constant speed. The coefficient of friction between the ice and incline is 0.10. Find the force exerted by the worker. (I&#...
*Wednesday, March 11, 2015 at 2:48am*

**Physics**

You count 9 cycles across 8.1 time divisions on an oscilloscope screen. The time sweep is set to 60 micro seconds. The voltage peak is measured to be 22 volts. What is the frequency? You plot some data of Real Frequency versus HP Dial Frequency and get a linear trend of y = 1....
*Wednesday, March 11, 2015 at 12:15am*

**Physics **

1. Given t1/2 to be 0.0137 seconds, how long should it take to reach 87.5% of maximum charge?
*Tuesday, March 10, 2015 at 11:37pm*

**Physics**

The coefficient of static friction between the m = 3.75-kg crate and the 35.0° incline of the figure below is 0.320. What minimum force vector F must be applied to the crate perpendicular to the incline to prevent the crate from sliding down the incline?
*Tuesday, March 10, 2015 at 10:37pm*

**Physics help please!**

1. Given t1/2 to be 0.0137 seconds, how long should it take to reach 87.5% of maximum charge? 2. Let's say you measure t1/2 to be 0.0137 seconds and the resistance in the circuit is 99 Ohms. Then what is the capacitance in micro Farads? 3.q = qmax(1 - e -t / τ) Using ...
*Tuesday, March 10, 2015 at 10:14pm*

**physics**

*please walk me through equation The patellar tendon attaches to the tibia at the tibial tuberosity. The tibial tuberosity is 7 cm from the center of the knee joint. The patellar tendon pulls at an angle of 35deg to the line passing through the tibial tuberosity and the center...
*Tuesday, March 10, 2015 at 9:51pm*

**Physics**

Zak, helping his mother rearrange the furniture in their living room, moves a 58.3 kg sofa 7.7 m with a constant force of 25 N. What is the work done by Zak on the sofa? Neglect friction. Answer in units of J. What is the average acceleration of the sofa? Answer in units of m/...
*Tuesday, March 10, 2015 at 7:43pm*

**Physics**

We want to find how much charge is on the electrons in a nickel coin. Follow this method. A nickel coin has a mass of about 5.7 g. a. Find the number of atoms in a nickel coin. Each mole (6.02 × 10^23 atoms) has a mass of about 57.9 g. Answer in units of atoms. b. Find ...
*Tuesday, March 10, 2015 at 7:29pm*

**Physics**

A charge q1 = 5 µC is at the origin, and a charge q2 = 4 µC is on the x axis at x = 6 m. Find the force on charge q2 . The Colulomb constant is 8.98755 × 10^9 N·m^2/C^2. Answer in units of N.
*Tuesday, March 10, 2015 at 7:23pm*

**Physics**

A strong lightning bolt transfers about 21.45 C to Earth. How many electrons are transferred? The elemental charge is 1.602 × 10^−19 C.
*Tuesday, March 10, 2015 at 7:22pm*

**physics**

A plastic rod is rubbed against a wool shirt, thereby acquiring a charge of −4.9 µC. How many electrons are transferred from the wool shirt to the plastic rod? The elemental charge is 1.6 × 10−19 C.
*Tuesday, March 10, 2015 at 5:52pm*

**physics**

You can estimate your distance from a lightning storm by watching for a lightning flash and then counting in one-second intervals using the general rule that you are 1 km away for every 3 s you count. Explain why this rule works. Estimate the distance from a lightning storm if...
*Tuesday, March 10, 2015 at 5:31pm*

**Physics**

If a mass of gasoline occupies 70.01 at 20°C, What is the volume at 35°C?
*Tuesday, March 10, 2015 at 4:31pm*

**Physics**

An object floats in a liquid of density 1.2×10 kg/m3 with one quarter of its volume above the liquid surface. You are required to determine the density of the object
*Tuesday, March 10, 2015 at 4:29pm*

**physics **

A system of 1216 particles, each of which is either an electron or a proton, has a net charge of -5.920×10-17 C. A)How many electrons are in this system (exactly)? B)What is the mass of this system (to three significant digits)?
*Tuesday, March 10, 2015 at 3:45pm*

**Physics**

Billy stands on a hill without slipping. In which direction is the force of friction acting?
*Tuesday, March 10, 2015 at 2:40pm*

**Physics College**

A heat engine operates in a Carnot cycle between 78.0°C and 340°C. It absorbs 22,000 J of energy per cycle from the hot reservoir. The duration of each cycle is 3.00 s. (a) What is the mechanical power output of this engine? (answer in kW) (b) How much energy does it ...
*Tuesday, March 10, 2015 at 2:01pm*

**physics**

calculate the linear speed of a point on the record at the beginning and the end of the record that rotates at 33rev/min r1=7cm,r2=15cm
*Tuesday, March 10, 2015 at 1:51pm*

**physics**

A car's wheel of radius r=50cm goes through 5000rev in 1min. find the car's average angular velocity,and how far it travels along the ground in 1min. The linear speed v and angular speed w of the point of a rotating body are connected by the equation v=wr. where r is ...
*Tuesday, March 10, 2015 at 1:43pm*

**Physics**

Hi guys, I was just wondering if I'm heading in the right direction with this question. Thank you so much in advance for your time!! A loudspeaker emits energy at the rate of 56W , spread in all directions. What is the intensity of sound 18m from the speaker? Working out (...
*Tuesday, March 10, 2015 at 11:42am*

**physics**

What design aspects of the snowmobile make it particulary useful for travel over ice and snow?
*Tuesday, March 10, 2015 at 11:36am*

**Physics**

Hello to all the fantastic tutors! I'm stuck on this question, I was wondering if there is a way to solve this. A car horn emits 378Hz sound. If the car moves at 23m/s with its horn blasting, what frequency will a person standing in front of the car hear? What I've ...
*Tuesday, March 10, 2015 at 11:33am*

**physics**

a car set out at noon to ride from point a to point b, and another car started at 2 pm on the same day to ride from point b to point a. they met on the road at 4:05 pm, and each car reached their destination at exactly the same time. at what time did the car arrive?(hint: both...
*Tuesday, March 10, 2015 at 9:27am*

**physics**

4. A ball is thrown so that it just clears a 3m fence 18m away. If it left the hand 1.5m above the ground and at an angle of 60° with the horizontal, what was the initial velocity of the ball?
*Tuesday, March 10, 2015 at 9:20am*

**physics**

a ball dropped from rest at a height of 50 m above the ground. (a) what is the speed just before it hits the ground? (b) how long does it take to reach the ground?
*Tuesday, March 10, 2015 at 7:41am*

**physics**

a car moving at 30 m/s slows to a speed of 10 m/s in a time of 5 s. determine a.) the acceleration of the car (b). the distance it moves in the third second.
*Tuesday, March 10, 2015 at 7:33am*

**physics**

You can estimate your distance from a lightning storm by watching for a lightning flash and then counting in one-second intervals using the general rule that you are 1 km away for every 3 s you count. Explain why this rule works. Estimate the distance from a lightning storm if...
*Monday, March 9, 2015 at 11:35pm*

**physics **

a 6 0 kg piece of aluminum at 645 degrees to celsius is combine with 1.0 kg of ice at -15 degrees Celsius in a thermally isolated calorimeter of negligible heat capacity what is the equalilbrum temperature the mixture evenually reaches?. q1+q2+q3=0 QAl = .6kg* .9kj/kg-K * ...
*Monday, March 9, 2015 at 10:51pm*

**Physics**

How close to the edge of the 24.0 kg table shown in Figure 9-47 can a 60.0 kg person sit without tipping it over? m Table is 2.2m long each leg is 5m into the table and there is 1.2m in between each leg. The table is 8m in height.
*Monday, March 9, 2015 at 10:44pm*

**physics**

The speedometer on an automobile measures the rotational speed of the axle and converts that to a linear speed of the car, assuming the car has 0.62-m-diameter tires. What is the rotational speed of the axle when the car is traveling at 26m/s ?
*Monday, March 9, 2015 at 9:49pm*

**physics**

A ballet student with her arms and a leg extended spins with an initial rotational speed of 0.90rev/s . As she draws her arms and leg in toward her body, her rotational inertia becomes 0.80 kg⋅m2 and her rotational velocity is 4.1rev/s . Determine her initial rotational ...
*Monday, March 9, 2015 at 9:49pm*

**physics**

Determine the change in rotational kinetic energy when the rotational velocity of the turntable of a stereo system increases from 0 to 33 rpm. Its rotational inertia is 6.8×10−3kg⋅m2 .
*Monday, March 9, 2015 at 9:48pm*

**Physics**

A container with a one-liter capacity at 27 degree C is filled with helium to a pressure of 2 atm. how many moles of helium does it hold?
*Monday, March 9, 2015 at 8:41pm*

**physics**

You need to lift a 200 kg box 5 meters, but it is too heavy. You decide to push it up an incline that makes a 25 degree angle with the ground. With what force do you need to push the box?
*Monday, March 9, 2015 at 8:38pm*

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