Wednesday

May 27, 2015

May 27, 2015

**physics**

A block of mass M1 = 15 kg is lying on a horizontal friction-less surface is connected to a string passing over a friction-less pulley. A mass of M2 = 25 kg is hanging at its other end as shown in the figure below. (i) Find the acceleration in the masses. (ii) What is the ...
*Monday, April 13, 2015 at 7:35am*

**Physics**

A sprinter crosses the finish line of a race. The roar of the crowd in front approaches her at a speed of 357m/s . The roar from the crowd behind her approaches at 341m/s . A) What is the speed of the sound? B) What is the sprinter's speed?
*Sunday, April 12, 2015 at 11:42pm*

**Physics**

You have 250 g of water in an aluminium calorimeter with a mass of 125 g. How long will it take to increase the temperature of the water and calorimeter from 20C to 37C if the system is heated by a resistive heating element with 8 V across the resistor and 0.75 A flowing ...
*Sunday, April 12, 2015 at 11:06pm*

**Physics**

A not so brilliant physics students wants to jump from their 3rd floor apartment window to the swimming pool below. The problem is the base of the apartment is 8.00 meters from the pool’s edge. If the window is 20.0 meters high, how fast does the student have to be ...
*Sunday, April 12, 2015 at 9:20pm*

**Physics**

3. A bullet is fired from at a shooting range. The bullet hits the ground after 0.32 seconds. How far did it travel horizontally and vertically in this time if it was fired at a velocity of 1100 m/s?
*Sunday, April 12, 2015 at 9:19pm*

**PHYSICS math**

2. An airplane is 50,000 m above an observer and 2.1 km to the west of them and 1.5 km to the north of you. Determine the angle to the plane in the x – y axis and the total distance to the plane from you. Choose the x-axis east, y axis north, and z axis up
*Sunday, April 12, 2015 at 9:18pm*

**Physics**

Stacy uses a close range telescope, which contains 2 converging lenses, each having a focal distance of 0.750 m, separated by a distance of 1.501 m. If she spots Jane, located a distance of 542 meters away, what is the magnification of the image she sees? is it upright or ...
*Sunday, April 12, 2015 at 8:29pm*

**physics**

A crane operator intends to lift a 300 kg piece of equipment using an upward force of 4000 N, will he be able to lift the equipment.
*Sunday, April 12, 2015 at 8:17pm*

**physics **

a boy drops a mango from a tree it falls without rebound what happens to it's momentum
*Sunday, April 12, 2015 at 5:42pm*

**PHYSICS**

Determine the resulting temperature when 1kg of ice at 0 Degree celcius is mixed with 9kg of water.
*Sunday, April 12, 2015 at 4:56pm*

**physics**

An electrical power plant generates electricity with a current of 50A and a potential difference of 20,000 V. In order to minimize the power losses due to the high current heating up the line, a transformer steps up the potential difference to 500,000 V before it is ...
*Sunday, April 12, 2015 at 4:45pm*

**physics**

An object whose moment of inertia is 2.5 kg · m^2 experiences the torque shown in the figure below. What is the object's angular velocity at t = 1.6 s? Assume it starts from rest. webassign[.]net[/]knight[/]p13-21[.]gif So far, I know that that to find the ...
*Sunday, April 12, 2015 at 4:00pm*

**physics**

1 The principle of conservation of heat energy states that that when an object is at constant temperature or is in thermal equilibrium, it is losing and gaining heat at equal rates. the heat lost by a hot body is equal to the heat gained by the cold body in any system provided...
*Sunday, April 12, 2015 at 3:53pm*

**physics**

1 The specific heat of a substance at its boiling point or melting point Is 0 Is infinity Is negative lies between 0 and 1 2 A unit mass of solid converted to liquid at its melting point. Heat is required for this process is Specific heat Latent heat of vaporization Latent ...
*Sunday, April 12, 2015 at 3:50pm*

**Physics**

The pressure of water flowing through a 6.5×10−2−m -radius pipe at a speed of 1.8m/s is 2.2 × 105 N/m2 What is the flow rate of the water? What is the pressure in the water after it goes up a 5.2−m -high hill and flows in a 5.0×10−2&#...
*Sunday, April 12, 2015 at 3:19pm*

**Physics**

A car with a total mass of 1800kg (including passengers) is driving down a washboard road with bumps spaced 5.0m apart. The ride is roughest—that is, the car bounces up and down with the maximum amplitude—when the car is traveling at 6.1 m/s.What is the spring ...
*Sunday, April 12, 2015 at 3:07pm*

**physics- Space**

How does the amount of dark matter in the Universe compare to the amount of ordinary matter? In what way is dark matter similar to ordinary matter? In what way are they different? I got the first one which dark matter is 23% of the universe. But for the other questions, the ...
*Sunday, April 12, 2015 at 1:40pm*

**Physics**

a freight train has two engines, each with a mass of 50,000 kg. pulling
*Sunday, April 12, 2015 at 8:55am*

**Physics**

In exercising, a weight lifter loses 0.236 kg of water through evaporation, the heat required to evaporate the water coming from the weight lifter's body. The work done in lifting weights is 1.41 x 105 J. (a) Assuming that the latent heat of vaporization of perspiration is...
*Sunday, April 12, 2015 at 6:21am*

**Physics, tempreture**

A rock of mass 0.234 kg falls from rest from a height of 28.9 m into a pail containing 0.492 kg of water. The rock and water have the same initial temperature. The specific heat capacity of the rock is 1840 J/kg C°. Ignore the heat absorbed by the pail itself, and ...
*Sunday, April 12, 2015 at 4:57am*

**Physics**

A uniform, 274-N rod that is 2.05m long carries a 225-N weight at its right end and an unknown weight W toward the left end.When W is placed 50.3cm from the left end of the rod, the system just balances horizontally when the fulcrum is located 78.0cm from the right end. i ...
*Sunday, April 12, 2015 at 12:50am*

**physics**

A concave mirror forms a real image twice as large as the object. The object is then moved such that the new real image produced is three times the size of the object. If the image was moved 94.1 cm from its initial position, how far was the object moved? I have no clue how to...
*Saturday, April 11, 2015 at 5:26pm*

**Physics **

You and your friends are doing physics experiments on a frozenpond that serves as a frictionless, horizontal surface. Sam,with mass 80.0 kg, is given a push and slides eastward. Abigail, with mass 50.0 kg, is sent sliding northward. Theycollide and after the collision, Sam is ...
*Saturday, April 11, 2015 at 1:55pm*

**physics**

a hollow spherical iron shell floats just completely submerged in water.the outer diameter is 50 cm and the density of iron is 7.9cm cubed .find he inner diameter of the shell
*Saturday, April 11, 2015 at 6:23am*

**Physics**

1kg of an unknown metal at 94 degrees C is placed in 100g of water at 10 degrees C. The final temperature of the metal and water are 17 degrees C. By finding specific heat capacity, identify the metal
*Saturday, April 11, 2015 at 3:39am*

**Physics**

The velocity of the Moon relative to the center of the Earth can be approximated by varrowbold(t) = v [−sin (ωt) xhatbold + cos (ωt) yhatbold], where v = 945 m/s and ω = 2.46 multiplied by 10−6 radians/s. (The time required for the Moon to complete ...
*Friday, April 10, 2015 at 9:43pm*

**math/physics**

A 8 kg mass is attached to a spring hanging from the ceiling and allowed to come to rest. assume that the spring constant is 40 n/ m and a damping constant is 3 N/m. At t=0 and external force of 2 sin(2t+PI/4)N is applied to the system. determine amp, frequency and steady ...
*Friday, April 10, 2015 at 12:53pm*

**PHYSICS**

A Hammer weighing 3kg strikes the head of a nail with a speed of 2m/s and drives it by 1cm into the wall. find the impulse?
*Friday, April 10, 2015 at 11:32am*

**physics**

A cat usually lands on its feet regardless of the position from which it is dropped. A slow-motion film of a cat falling shows that the upper half of its body twists in one direction while the lower half twists in the opposite direction. (See figure below.) Why does this type ...
*Friday, April 10, 2015 at 11:19am*

**physics**

a car moves from A to B covering a distance of 1000km it covers the first 300km at 60km/h the next 400km at 80 km /h at what speed it should it cover the remaining distance so that achieve an average speed of 70km/h?
*Friday, April 10, 2015 at 7:19am*

**Physics**

Is this correct?? Metal block weighs 500g in air and 446g completely submerged in water. Calculate density and relative density. Density of water = 1000kg/m3 BF (Buoyant force) will be 500g-446g = 0.54 g (or 0.054 kg). For volume: If BF = Density(water)*V*g then V = BF/density...
*Friday, April 10, 2015 at 6:45am*

**physics**

a car moves from car A to B covering a distance of 600km/h if it covers first 400km at 80km/h and the other remaining at 100km/h .What is the average speed for entire journey
*Friday, April 10, 2015 at 6:01am*

**physics**

a cyclist moves around equilateral triangle6kn/h10km/h,12km/hfind average speed?
*Friday, April 10, 2015 at 5:25am*

**physics. urgent answer please**

Two forces 10 N acting in the direction N 30 east and 15 N acting in the eastern direction, if both forces act at a point, find the magnitude and direction of (a) the resultant force (b) the equilibriant force.
*Friday, April 10, 2015 at 4:24am*

**Physics**

An atomic nucleus at rest decays radioactively into an alpha particle and a nucleus smaller than the original. What will be the speed of this recoiling nucleus if the speed of the alpha particle is 2.20E+05 m/s? Assume the recoiling nucleus has a mass 54 times as great as that...
*Friday, April 10, 2015 at 2:21am*

**ANSWER ASAP!!!!!!! PHYSICS**

a small airplane is dropping a probe in a remote area in antarctica in a narrowly specified location. the probe in a protective shell can not land any harder than with a maximum speed of 60m/sec at landing, while the plane has to move at a minimum speed of 30m/sec horizontally...
*Friday, April 10, 2015 at 1:47am*

**NEED HELP ASAP PHYSICS@!!1**

Tarzan (m = 78.4 kg) tries to cross a river by swinging from a vine. The vine is 10 m long. Tarzan doesn't know that the vine has a breaking strength of 1045 N. What maximum speed (in m/s) can Tarzan have at the bottom of the swing (as he just clears the water) in order to...
*Friday, April 10, 2015 at 1:27am*

**NEED HELP ASAP PHYSICS@!!1**

A person is flying a model airplane with mass 82.2 gram in a horizontal circular path on the end of a string 10.5 m long. The string is horizontal and exerts a force of 3.22 N on the hand of the person holding it. What is the speed (in m/s) of the plane? PLEASE PLEASE PLEASE ...
*Friday, April 10, 2015 at 1:26am*

**Physics**

In about 1915, Henry Sincosky of Philadelphia suspended himself from a rafter by gripping the rafter with the thumb of each hand on one side and the fingers on the other side (see the figure). Sincosky's mass was 87.6 kg. If the coefficient of static friction between hand ...
*Thursday, April 9, 2015 at 11:00pm*

**physics**

How can the alternative definition of power: P = \frac{w}{\Delta t} = F \frac{d}{\Delta t} ... can be derived by substituting the definitions of work and speed into the standard definition of power, P =\frac{W}{\Delta t}. (Equations written without latex formatting:) P = w/...
*Thursday, April 9, 2015 at 2:38pm*

**Physics**

A block of mass 0.65 kg and density 650 kg/m³ is forced under the surface of the water by means of a spring (k = 60.0 N/m) that is fixed to the bottom of the container as shown in the figure. How much is the spring stretched? (the density of water is 1000 kg/m³).
*Thursday, April 9, 2015 at 1:27pm*

**Physics**

Water at a pressure of 3.90 atm at street level flows into an office building at a speed of 0.45 m/s through a pipe 5.60 cm in diameter. The pipes taper down to 2.10 cm in diameter by the top floor, 26.0 m above. Calculate the water pressure in such a pipe on the top floor.
*Thursday, April 9, 2015 at 1:26pm*

**Physics**

A large container, 114 cm deep is filled with water. If a small hole is punched in its side 93.0 cm from the top, at what initial speed will the water flow from the hole?
*Thursday, April 9, 2015 at 1:26pm*

**Physics**

A raft is made of 14 logs lashed together. Each is 29.5 cm in diameter and has a length of 6.50 m. How many people (whole number) can the raft hold before they start getting their feet wet, assuming the average person has a mass of 75.0 kg? Do not neglect the weight of the ...
*Thursday, April 9, 2015 at 1:26pm*

**physics**

A 42.5 g marble is fired vertically upward using a spring gun. The spring must be compressed 7.0 cm if the marble is to reach a target 27.0 m above the gun. What is the change in gravitational energy of the marble during its ascent?
*Thursday, April 9, 2015 at 12:11pm*

**physics**

'2 balls of mass ratios 1:2 are dropped from the same height. State the ratio between their velocities when they strike the ground, the ratio of forces acting on them during motion.'
*Thursday, April 9, 2015 at 11:23am*

**PHYSICS**

In a power plant the high pressure turbine trips due to an unauthorised valve shutdown. What are a) what is the angular acceleration of the turbine blade? b) what is the distance travelled by a point on the rim of the turbine blade during the acceleration? c) what is the ...
*Thursday, April 9, 2015 at 8:28am*

**Physics**

Two forces 10 N acting in the direction N 30 east and 15 N acting in the eastern direction, if both forces act at a point, find the magnitude and direction of (a) the resultant force (b) the equilibriant force.
*Thursday, April 9, 2015 at 7:15am*

**Physics**

A spring of length 10.0 cm and spring constant 160 kN/m is compressed to a length of 4.00 cm. If, when released, it pushes a block of mass 100 kg, a) what is the speed of the block after it slides up a 15.0 cm hill? b) What is its speed after it falls into a 10.0 cm dip?
*Thursday, April 9, 2015 at 7:10am*

**physics**

An airplane is flying horizontally at a velocity of 50.0 m/s at an altitude of 125 m. It drops a package to observers on the ground below. Approximately how far will the package travel in the horizontal direction from the point that it was dropped
*Thursday, April 9, 2015 at 3:15am*

**Physics **

A 4-person bobsled team pushes the 330 kg sled down the 6.0 degree hill with a force of 1780 N. The coefficient of friction for ice and the runner is 0.135. How fast will the sled be moving at the end of the 40m push? Answer is in meters/second
*Thursday, April 9, 2015 at 12:32am*

**Physics **

You're driving along at 101 km/hr on a rainy day. Suddenly a deer jumps out 30 m ahead of you. You slam on the brakes of your 1972 Mustang (no ABS) with Goodyear tires (coefficient of kinetic friction= 0.525, coefficient of static friction=0.750). Will you hit the deer?
*Thursday, April 9, 2015 at 12:30am*

**physics**

A block of mass m1 = 3.08 kg on a friction less plane inclined at angle θ = 32.3° is connected by a cord over a massless, frictionless pulley to a second block of mass m2 = 2.51 kg hanging vertically (see the figure). (a) What is the acceleration of the hanging block...
*Wednesday, April 8, 2015 at 11:55pm*

**Physics**

A converging lens (f = 27.5 cm) is used to project an image of an object onto a screen. The object and the screen are 113 cm apart, and between them the lens can be placed at either of two locations. Find the two object distances. (Enter your answers from smallest to largest...
*Wednesday, April 8, 2015 at 10:34pm*

**Physics**

An object is 21 cm in front of a diverging lens that has a focal length of -13 cm. How far in front of the lens should the object be placed so that the size of its image is reduced by a factor of 1.5? my work: 1/di=(1/-13)-(1/21) di=-8.02 m=8.02/21 m=.381 m2=-.381/1.5 m2=-.254...
*Wednesday, April 8, 2015 at 10:31pm*

**physics**

An object is released from rest at an unknown height h above the ground. One second later a second object is released from rest at the same height. When the first object strikes the ground, the second is 20 m above the ground. What is the initial height h?
*Wednesday, April 8, 2015 at 8:58pm*

**Physics **

A football player pushes a tackling dummy forwards at a constant speed for 111m using 7150J of energy. b)What is the frictional force the dummy exerts? c)What work is done by friction as the dummy is slid along the field for 11m? omg please help I am so lost
*Wednesday, April 8, 2015 at 7:55pm*

**need HELP PHYSICS!!**

a) Calculate the P.E. a pile driver has if it is raised 4.5 meters by a mechanical winch. If the 510 kilogram pile driver is allowed to fall freely, what would its velocity be at ground level. b) A 4.2 kg mortar shell is fired out of a mortar with a velocity of 120 m/s. What ...
*Wednesday, April 8, 2015 at 7:54pm*

**PHYSICS**

In a power plant the high pressure turbine trips due to an unauthorised valve shutdown. What are a) what is the angular acceleration of the turbine blade? b) what is the distance travelled by a point on the rim of the turbine blade during the acceleration? c) what is the ...
*Wednesday, April 8, 2015 at 6:42pm*

**Physics**

What is the mass of a child if the force of gravity on the child's body is 100 N? A. 9.8 kg B. 4.45 kg C. 22.5 kg D. 10.2 kg what?
*Wednesday, April 8, 2015 at 6:35pm*

**AP Physics**

A racing car travels on a circular track of radius 220 m, moving with a constant linear speed of 48.9 m/s. Find its angular speed. Answer in units of rads/s. I already mutiplied 2π x 220. But I don't know what to do from there? Any help please? Thanks!
*Wednesday, April 8, 2015 at 6:06pm*

**Physics**

If a tank contains water 4 m deep, what is the pressure at the bottom of the tank? (Neglect the atmospheric pressure.) A. 39.2 kPA B. 18.9 kPA C. 4.0 kPa D. 9.8 kPA Im really lost
*Wednesday, April 8, 2015 at 6:01pm*

**PHYSICS**

In a power plant the high pressure turbine trips due to an unauthorised valve shutdown. What are a) what is the angular acceleration of the turbine blade? b) what is the distance travelled by a point on the rim of the turbine blade during the acceleration? c) what is the ...
*Wednesday, April 8, 2015 at 5:54pm*

**physics**

A wave traveling along the x axis is described mathematically by the equation y = 0.16 sin (9.0πt - 0.58πx), where y is the displacement (in meters), t is in seconds, and x is in meters. What is the speed of the wave?
*Wednesday, April 8, 2015 at 5:52pm*

**PHYSICS**

Calculate the work done against external atmospheric pressure when 1 g of water changes to 1672cm3 of steam. Take the atmospheric pressure as 1.013×105Nm−2
*Wednesday, April 8, 2015 at 5:11pm*

**PHYSICS**

A dock worker is loading a 25 kg solid cylindrical barrel to a ship by rolling it up a 9 meter long and 1.5 meter high ramp. At the top of the ramp the dock worker stop to go around the barrel but he loses the grip and the barrel starts to roll down the ramp without slipping ...
*Wednesday, April 8, 2015 at 5:08pm*

**PHYSICS**

Tin melts at 232 under standard atmospheric pressure. Express this temperature in kelvin
*Wednesday, April 8, 2015 at 4:25pm*

**Physics**

A girl is sledding down a slope that is inclined at 30º with respect to the horizontal. The wind is aiding the motion by providing a steady force of 131 N that is parallel to the motion of the sled. The combined mass of the girl and the sled is 59.9 kg, and the ...
*Wednesday, April 8, 2015 at 2:50pm*

**Physics**

39. (Taken from problem 5 at the end of Chapter 9) Look at the children balanced on the see-saw in the figure below. r1 = 1.60 m. The center mass of the seesaw is located 0.16 m to the left of the pivot point. The seesaw board has a mass of 12.0 kg which produces a weight of (...
*Wednesday, April 8, 2015 at 11:07am*

**Physics**

The drawing shows a circus clown who weighs 750 N. The coefficient of static friction between the clown’s feet and the ground is 0.630. He pulls vertically downward on a rope that passes around three pulleys and is tied around his feet. What is the minimum pulling force ...
*Wednesday, April 8, 2015 at 11:04am*

**physics**

A 102-kg man stands in an elevator that has an upward acceleration of 4.1 m/s2. The magnitude of the force exerted by him on the floor is about (g = 10 m/s2):
*Wednesday, April 8, 2015 at 7:28am*

**Physics**

Two spheres A and B of equal mass are free to move on a smooth horizontal surface. A and B move towards each other with velocity vectors ai+bj and ci+dj r respectively and collide when the line joining their centres is parallel to i. After impact A and B have velocity vectors ...
*Wednesday, April 8, 2015 at 6:38am*

**physics**

a car of the mass m kg travels on a straight,level road. the driving force of the engine is 4000N and the total resistance due to air friction and tires on the road is 300N. if the car accelerates at 3m/s2 ,what is the mass m of the car
*Wednesday, April 8, 2015 at 3:30am*

**Physics**

When a particular wire is vibrating with a frequency of 3.8 Hz, a transverse wave of wavelength 46 cm is produced. Determine the speed of wave pulses along the wire. Answer in units of m/s.
*Wednesday, April 8, 2015 at 1:34am*

**physics**

what is relative velocity?Answer with an example & description also a diagram.
*Wednesday, April 8, 2015 at 1:04am*

**Physics**

A spinning wheel is slowed down by a brake, giving it a constant angular acceleration of −4.60 rad/s2. During a 2.60-s time interval, the wheel rotates through 85.4 rad. What is the angular speed of the wheel at the end of the 2.60-s interval?
*Wednesday, April 8, 2015 at 12:24am*

**physics**

Friction provides the force needed for a car to travel around a flat, circular race track. What is the maximum speed at which a car can safely travel if the radius of the track is 80.0 m and the coefficient of friction is 0.43?
*Wednesday, April 8, 2015 at 12:20am*

**Physics**

A skateboarder approaches the circular hill with a velocity of 8.0 m/s at point B. The angle formed between the lines that join point AO and BO is 20 degrees. a) what is her speed at the top of the hill(Point A) if she coasts up to this point? b) what min speed must she have ...
*Tuesday, April 7, 2015 at 10:37pm*

**Physics **

a blood centrifuge starts from rest and attains a rotational speed of 3400 rpm after 50 seconds. 1) determine average angular acceleration of the centrifgue 2) a 3ml blood sample is contained in a test tube at distance 37.5mm from the centreline. Calculate average centripetal ...
*Tuesday, April 7, 2015 at 10:37pm*

**Physics !**

Three identical light bulbs are connected in series, then are disconnected and arranged in parallel. For each of the scenarios below indicate what changes (if any) take place A. Total resistance of the circuit B. Total current of the circuit C. Power dissipated by the circuit ...
*Tuesday, April 7, 2015 at 9:50pm*

**Physics!**

An ammeter indicates the current for a toaster is 5.0 amps when the toaster is connected to 120-V circuit. How much energy is given off by the toaster in 42.0 seconds? Show all calculations leading to an answer.
*Tuesday, April 7, 2015 at 9:28pm*

**physics**

The figure below shows a clawhammer as it is being used to pull a nail out of a horizontal board. A force of magnitude 130 N is exerted horizontally as shown. (NOTE: Assume that the force the hammer exerts on the nail is parallel to the nail and perpendicular to the position ...
*Tuesday, April 7, 2015 at 8:34pm*

**Physics!**

An ammeter indicates the current for a toaster is 5.0 amps when the toaster is connected to 120-V circuit. How much energy is given off by the toaster in 42.0 seconds? show all the calculations leading to your answer
*Tuesday, April 7, 2015 at 6:22pm*

**physics**

a 16.0-g bullet is shot into a wooden block at rest with mass 4550g on a frictionless surface. the block moves 1.20m/s after the bullet strikes and becomes lodged in the block. find the speed of the bullet before striking the block.
*Tuesday, April 7, 2015 at 5:53pm*

**physics**

You hold a hose 45 degrees to the horizontal and at a height of 1 m from the floor. The water reaches a maximum distance of 10 m from where you are standing. Now you place your thumb over the end of the hose to occlude the opening by 80%, which in turn reduces the flow rate by...
*Tuesday, April 7, 2015 at 5:45pm*

**physics**

Assume the muscle is 37C and is separated from the outside air by layers of fat and skin. The layer of fat, at a particular location on the skin, is 2 mm thick and has a conductivity of 0.53 W/mK. Finally, the outermost epidermal layer is 0.1 mm thick with a thermal ...
*Tuesday, April 7, 2015 at 5:30pm*

**physics**

one car of mass 15.0kg is moving 5.00m/s to the right on a frictionless track and collides with a cart of mass 3.00kg. the final velocity of the carts that become stuck together after the collision is 1.50m/s to the right. find the velocity of the second cart before the ...
*Tuesday, April 7, 2015 at 5:30pm*

**physics**

A worker has to move a rock with mass 50 kg on a stairway from the first floor to the second floor of a house. The second floor is 4.6 m above the first floor and the stairway has 18 steps. The rock is lifted from step to step. How much energy (in Joule) has to be spend to ...
*Tuesday, April 7, 2015 at 5:27pm*

**physics**

A 13.1-g bullet is fired into a block of wood at 261 m/s. The block is attached to a spring that has a spring constant of 205 N/m. The block and bullet continue to move, compressing the spring by 35.0 cm before the whole system momentarily comes to a stop. Assuming that the ...
*Tuesday, April 7, 2015 at 4:47pm*

**physics**

From her bedroom window a girl drops a water-filled balloon to the ground, 4.75 m below. If the balloon is released from rest, how long is it in the air?
*Tuesday, April 7, 2015 at 4:32pm*

**Physics**

A ball is thrown vertically upward, which is the positive direction. A little later it returns to its point of release. The ball is in the air for a total time of 8.11 s. What is its initial velocity? Neglect air resistance.
*Tuesday, April 7, 2015 at 4:32pm*

**Physics**

You are driving your car, and the traffic light ahead turns red. You apply the brakes for 2.28 s, and the velocity of the car decreases to + 4.76 m/s. The car’s deceleration has a magnitude of 2.99 m/s2 during this time. What is the car’s displacement?
*Tuesday, April 7, 2015 at 4:31pm*

**Physics**

In an historical movie, two knights on horseback start from rest 79.7 m apart and ride directly toward each other to do battle. Sir George's acceleration has a magnitude of 0.323 m/s2, while Sir Alfred's has a magnitude of 0.252 m/s2. Relative to Sir George's ...
*Tuesday, April 7, 2015 at 4:30pm*

**Physics**

A motorcycle has a constant acceleration of 2.65 m/s2. Both the velocity and acceleration of the motorcycle point in the same direction. How much time is required for the motorcycle to change its speed from (a) 41.5 to 51.5 m/s, and (b) 71.5 to 81.5 m/s?
*Tuesday, April 7, 2015 at 4:29pm*

**Physics**

A girl is sledding down a slope that is inclined at 30º with respect to the horizontal. The wind is aiding the motion by providing a steady force of 131 N that is parallel to the motion of the sled. The combined mass of the girl and the sled is 59.9 kg, and the ...
*Tuesday, April 7, 2015 at 4:10pm*

**PHYSICS**

A spring gun, held horizontally 1.70 m above the ground, fires a 0.010 kg marble so that it lands a horizontal distance of 7.60 m away. If the gun is pointed straight up, and the same marble is fired, how high (in meters) will it rise? I tried using h=1/2gt^2 and then Vf = Vi-...
*Tuesday, April 7, 2015 at 3:54pm*

**Physics**

The drawing shows a circus clown who weighs 750 N. The coefficient of static friction between the clown’s feet and the ground is 0.630. He pulls vertically downward on a rope that passes around three pulleys and is tied around his feet. What is the minimum pulling force ...
*Tuesday, April 7, 2015 at 3:47pm*

**Physics**

During a storm, a tree limb breaks off and comes to rest across a barbed wire fence at a point that is not in the middle between two fence posts. The limb exerts a downward force of 246 N on the wire. The left section of the wire makes an angle of 14.2° relative to the ...
*Tuesday, April 7, 2015 at 3:46pm*

**Physics**

The person in the drawing is standing on crutches. Assume that the force exerted on each crutch by the ground is directed along the crutch, as the force vectors in the drawing indicate. If the coefficient of static friction between a crutch and the ground is 0.705, determine ...
*Tuesday, April 7, 2015 at 3:46pm*

**Physics**

A mountain climber, in the process of crossing between two cliffs by a rope, pauses to rest. She weighs 530 N. As the drawing shows, she is closer to the left cliff than to the right cliff, with the result that the tensions in the left and right sides of the rope are not the ...
*Tuesday, April 7, 2015 at 3:46pm*