Friday

July 31, 2015

July 31, 2015

**physics**

Three blocks A, B, and C are connected by two massless strings passing over smooth pulleys as shown below, with the 3.4-kg block on a smooth horizontal surface. Calculate the tension in the strings connecting A and B, and, B and C.
*Friday, December 5, 2014 by bob*

**Physics**

The brakes of a bike (with a person) having a mass of 63 kg, reduces it's velocity from 8.5 m/s to 0 m/s in 3.0 seconds. What is the magnitude of braking force?
*Friday, December 5, 2014 by Jennifer*

**Physics**

A solid cylinder of mass 20 kg rotates about its axis with angular speed of 100 rad/sec. the radius of the cylinder is 0.25m. what is the kinetic energy of the cylinder?
*Friday, December 5, 2014 by Devnet*

**Physics**

super mouse steals a large piece of cheese by rolling it across the floor with a force of 5.0 N. If the cheese has a mass of 50 kg with what acceleration does the cheese move? If super mouse's force remains constant, what will be the speed of the rolling cheese
*Friday, December 5, 2014 by Jennifer*

**Physics**

A 1600 kg car traveling at 13.7 m/s to the south collides with a 4600 kg truck that is initially at rest at a stoplight. The car and truck stick together and move together after the collision. What is the final velocity of the two-vehicle mass? Assume that North is positive. ...
*Friday, December 5, 2014 by help me!*

**Physics**

What is the force of attraction between an 8 kg bowling ball and a 13 kg cannon ball that are sitting 2 meters apart?
*Friday, December 5, 2014 by Anonymous *

**physics**

Sound is passing perpendicularly through an open window whose dimensions are 1.1 m x 0.75 m. The sound intensity level is 71 dB above the threshold of human hearing. How much sound energy comes through the window in one hour?
*Friday, December 5, 2014 by Anonymous*

**physics**

A man stands at the midpoint between two speakers that are broadcasting an amplified static hiss uniformly in all directions. The speakers are 28.0 m apart and the total power of the sound coming from each speaker is 0.602 W. Find the total sound intensity the man hears when (...
*Friday, December 5, 2014 by Anonymous*

**physics**

When an earthquake occurs, two types of sound waves are generated and travel through the earth. The primary, or P, wave has a speed of about 8.0 km/s and the secondary, or S, wave has a speed of about 4.5 km/s. A seismograph, located some distance away, records the arrival of ...
*Friday, December 5, 2014 by Anonymous*

**physics**

A jetskier is moving at 8.9 m/s in the direction in which the waves on a lake are moving. Each time he passes over a crest, he feels a bump. The bumping frequency is 1.15 Hz, and the crests are separated by 5.8 m. What is the wave speed?
*Friday, December 5, 2014 by Anonymous*

**physics**

The speed of a transverse wave on a string is 457 m/s, while the wavelength is 0.228 m. The amplitude of the wave is 2.05 mm. How much time is required for a particle of the string to move through a total distance of 1.34 km?
*Friday, December 5, 2014 by Anonymous*

**physics**

A roller coaster, loaded with passenger has a mass of 2000 kg; the radius of curvature of the track at the bottom point of the dip is 24 m. If the vehicle has a speed of 18m/s at this point, what force is exerted on the vehicle by the track? (g = 9.8 m/s2)
*Friday, December 5, 2014 by hilmar*

**Physics**

An object is placed 5 cm in front of a concave lens of focal length 7 cm. Find the image location by drawing a ray tracing diagram to scale. Verify your answer using the lens equation. I am confused on what numbers would be negative in my formula of 1/f=1/v+1/u.
*Friday, December 5, 2014 by Frank German*

**physics**

An object is placed 8 cm in front of a convex lens of focal length 6 cm. Find the image location by drawing a ray tracing diagram to scale. Verify your answer using the lens equation
*Thursday, December 4, 2014 by Frank German*

**physics**

Two lifeguards pull on ropes attached to a raft. If they pull in the same direction, the raft experiences a net external force of 376 N to the right. If they pull in opposite directions, the raft experiences a net external force of 162 N to the left. Draw a free body diagram ...
*Thursday, December 4, 2014 by allan*

**physics **

Due to a tune-up, the efficiency of an automobile engine increases by 4.00%. For an input heat of 1530 J, how much more work does the engine produce after the tune-up than before?
*Thursday, December 4, 2014 by S*

**physics**

According to the manual of a certain car, a maximum torque of magnitude 76.0 N · m should be applied when tightening the lug nuts on the vehicle. If you use a wrench of length 0.276 m and you apply the force at the end of the wrench at an angle of 75.00° with ...
*Thursday, December 4, 2014 by sam*

**physics help PLZ!!**

What is the direction of the net external force on the crate (as an angle between −180◦ and 180◦ , measured from the positive x axis with counterclockwise positive)? Answer in units of ◦ Ive solved for the net external force in the x and y direction. Fx...
*Thursday, December 4, 2014 by allan*

**Physics**

Help!! I would greatly appreciate help with this question. Consider a pulse of laser light aimed at the Moon that bounces back to Earth. The distance between Earth and the Moon is 3.84 * 108 m. Show that the round-trip time for the light is 2.56s.
*Thursday, December 4, 2014 by Anne*

**Physics**

You have a brass ring of inside diameter 10.00 cm that is at 20.0oC. You want to slip this ring over an aluminum rod that is at 20.0oC and has a diameter of 10.01 cm. a. To what temperature do you have to heat the ring to slip it over the rod? b. Once you have the ring over ...
*Thursday, December 4, 2014 by David*

**ap physics**

a 37.4-kg traffic light is supported by two wires prove you answer applying newtons law
*Thursday, December 4, 2014 by michelle*

**Physics**

A 31.5 N object is in free fall. What is the magnitude of the net force which acts on the object? Answer in units of N
*Thursday, December 4, 2014 by Jennifer*

**physics**

A crate is pulled to the right with a force of 93.5 N, to the left with a force of 116.8 N, upward with a force of 658.1 N, and downward with a force of 248.6 N. What is the net external force in the x direction? Answer in units of N
*Thursday, December 4, 2014 by allan*

**Physics**

Batman (mass = 75.6 kg) jumps straight down from a bridge into a boat (mass = 631 kg) in which a criminal is fleeing. The velocity of the boat is initially +10.4 m/s. What is the velocity of the boat after Batman lands in it?
*Thursday, December 4, 2014 by Candice*

**Physics**

A 2.86-g bullet, traveling at a speed of 452 m/s, strikes the wooden block of a ballistic pendulum, such as that in Figure 7.14. The block has a mass of 230 g. (a) Find the speed of the bullet/block combination immediately after the collision. (b) How high does the combination...
*Thursday, December 4, 2014 by Candice*

**Physics**

A projectile, fired with unknown initial velocity, lands 18.4 s later on the side of a hill, 2740 m away horizontally and 469 m vertically above its starting point. (Ignore any effects due to air resistance.) (a) What is the vertical component of its initial velocity? 115.741 ...
*Thursday, December 4, 2014 by Anonymous*

**physics**

A projectile is fired into the air from the top of a cliff of height h = 186 m above a valley. Its initial velocity is v0 = 64.8 m/s at an angle θ = 59° above the horizontal. Where does the projectile land? (Ignore any effects due to air resistance.)
*Thursday, December 4, 2014 by Anonymous*

**Physics**

Question: A force of 25N pushes a curling rock from rest 1.0 m across a frictionless surface. Find the FINAL kinetic energy. attempts: Well i guess it would be changeinEk so i tried Wnet=changeinEk fnet x changeinD = 1/2mvf^2-1/2mvi^2 to fnet x changeinD +1/2mvi^2=1/2mvf^2 ...
*Thursday, December 4, 2014 by Anonymous*

**physics**

A 90-kilogram physics student would weigh 2970 Newtons on the surface of planet X. What is the magnitude of the acceleration due to gravity on the surface of planet X?
*Thursday, December 4, 2014 by tyler*

**Physics**

Question: A force of 25N pushes a curling rock from rest 1.0 m across a frictionless surface. Find the FINAL kinetic energy. attempts: Well i guess it would be changeinEk so i tried Wnet=changeinEk fnet x changeinD = 1/2mvf^2-1/2mvi^2 to fnet x changeinD +1/2mvi^2=1/2mvf^2 ...
*Thursday, December 4, 2014 by Anonymous*

**physics**

A blue puck has a velocity of 3i –4j m/s. Its mass is 20 kg. What is its momentum?
*Thursday, December 4, 2014 by alex*

**physics**

A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.30 m × 2.22 m. On a certain day, the indoor temperature is 22°C and the outdoor temperature is 0°C. (Assume the thermal conductivity of the glass is 0.8 J/s · m · °C.) What is...
*Thursday, December 4, 2014 by KEVIN*

**physics **

If the acceleration due to gravity on the earth is 9.8 m/s2, what is the acceleration due to gravity on Rams?
*Thursday, December 4, 2014 by joe*

**physics**

A projectile is fired into the air from the top of a cliff of height h = 186 m above a valley. Its initial velocity is v0 = 64.8 m/s at an angle θ = 59° above the horizontal. Where does the projectile land? (Ignore any effects due to air resistance.)
*Thursday, December 4, 2014 by Anonymous*

**physics**

A river 400 m wide is flowing at a rate of 2.0 m/s. A boat is sailing at a velocity of 10 m/s with respect to the wate, in a direction perpendicular to the river. (a) Find the time taken by the boat to reach the opposite bank. (b) How far from the point directly opposite to ...
*Thursday, December 4, 2014 by Md.Hayatullah*

**physics**

A stone thrown horizontally from the top of a 18-m tower hits the ground at a point 18 m from the base of the tower. (Ignore any effects due to air resistance.) (a) Find the speed at which the stone was thrown. m/s (b) Find the speed of the stone just before it hits the ground...
*Thursday, December 4, 2014 by Anonymous*

**physics**

A 0.59 kg rubber ball has a speed of 1.50 m/s at point A and kinetic energy of 7.0 J at point B. (a) Determine the ball's kinetic energy at A Correct: Your answer is correct. J (b) Determine the ball's speed at B
*Wednesday, December 3, 2014 by kelly*

**Physics**

A two head collision. One car weighs 45000 newtons and going at 15 meters per second. The other car is traveling at 25 meters per second and weighs 9000 newtons. How would I calculate velocity?
*Wednesday, December 3, 2014 by Emily Carey*

**Physics**

You throw a ball towards a wall at 15ms-1, and it bounces back at 10ms-1. What is the total change in velocity? (the answer is not 5m/s)
*Wednesday, December 3, 2014 by Juan*

**physics**

A 58.0 kg pole vaulter running at 8.9 m/s vaults over the bar. If the vaulter's horizontal component of velocity over the bar is 1.0 m/s and air resistance is disregarded, how high was the jump?
*Wednesday, December 3, 2014 by kelly*

**physics **

Dolphins of the open ocean are classified as Type II Odontocetes (toothed whales). These animals use ultrasonic "clicks" with a frequency of 54.9 kHz to navigate and find prey. Suppose a dolphin sends out a series of clicks that are reflected back from the bottom of ...
*Wednesday, December 3, 2014 by Peyton *

**physics **

A guitar string 61.8 cm long vibrates with a standing wave that has three antinodes. Which harmonic is this?
*Wednesday, December 3, 2014 by Peyton *

**College Physics**

Suppose a 10.0 kg fireworks shell is shot into the air with an initial velocity of 62.0 m/s at an angle of 80.0 degrees above the horizontal. At the highest point of its trajectory, a small explosive charge separates it into two pieces, neither of which ignite (two duds). One ...
*Wednesday, December 3, 2014 by Marqueta*

**Physics**

A block of mass m is pulled across a level surface by a rope that makes an angle θ with the horizontal. The coefficient of friction is μ. (a) Determine the amount of force F required to slide the block at a constant velocity. (b) Determine the optimum angle at which ...
*Wednesday, December 3, 2014 by Liz*

**physics**

A man pushes 100.0 N on the handle of a 40.0 kg lawnmower. The applied force is in the same direction as the handle, which is tilted 35.0° relative to horizontal. The coefficient of kinetic friction is 0.10. Find the amount of acceleration.
*Wednesday, December 3, 2014 by Liz*

**physics**

An object of mass 2.0 kg starts from rest at the top of a frictionless curved ramp. At the bottom, it collides with and sticks to another 2.0-kg mass object. Together the objects then cross a small rough section where there is friction before leaving the edge of the table ...
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

The engine of an automobile develops 176 hp when rotating at a speed of 1340 rpm. What torque (in foot-pounds) does it deliver? I tried using some kinematic equations, but that didnt work at all. Then I tried doing something where I would take an integral, but then I dont know...
*Wednesday, December 3, 2014 by Anon*

**physics**

a glider with a mass of 5 kg is moving to the right on a horizontal frictionless surface at 6 m/s when it collides with a 8 kg glider that is at rest. After the collision, the 8kg glider is moving to the right at 6 m/s. what are the speed and direction of the 5 kg glider ?
*Wednesday, December 3, 2014 by Alex*

**physics**

A uniform ladder of mass 46 kg and 3.0 m in length is leaning against a frictionless vertical wall at an inclination of 60 degrees to the horizontal. A Window cleaner of mass 67.3 kg climbs up the ladder. What coefficient of friction between the ladder and ground is required ...
*Wednesday, December 3, 2014 by Bren*

**physics**

Two identical guitar strings under 108 N of tension sound tones with frequencies of 528 Hz. The peg of one string slips slightly, and the tension in it drops to 91.0 N. How many beats per second are heard?
*Wednesday, December 3, 2014 by Jeanette*

**Physics**

What's the difference between Inertia and Impulse? Because the definitions sound really similar.
*Wednesday, December 3, 2014 by Devynn Austin*

**physics**

A 2.9-kg cart starts up an incline with a speed of 2.7 m/s and comes to rest 3.0 m up the incline. The total work done (the work of the net force) on the cart is:
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

Geologists place tiltmeters on the sides of volcanoes to measure the displacement of the surface as magma moves inside the volcano. Although most tiltmeters today are electronic, the traditional tiltmeter, used for decades, consisted of two or more water-filled metal cans ...
*Wednesday, December 3, 2014 by Dib*

**PHYSICS **

A diving board length L = 5.20m that weighs 205N is supported by two pillars. One pillar is at the left end of the diving board, as shown below; the other is distance d = 1.70m away. Find the magnitude of the force exerted by the left pillar when a 90.0kg diver stands at the ...
*Wednesday, December 3, 2014 by Lauren*

**Physics**

A projectile, fired with unknown initial velocity, lands 18.4 s later on the side of a hill, 2740 m away horizontally and 469 m vertically above its starting point. (Ignore any effects due to air resistance.) (a) What is the vertical component of its initial velocity? m/s (b) ...
*Wednesday, December 3, 2014 by Anonymous*

**physics**

if the radius from the discus to the axis of rotation is 1.4m, what is the linear velocity of the discus at the time of release?
*Wednesday, December 3, 2014 by Andrew*

**Physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

A projectile, fired with unknown initial velocity, lands 18.4 s later on the side of a hill, 2740 m away horizontally and 469 m vertically above its starting point. (Ignore any effects due to air resistance.) (a) What is the vertical component of its initial velocity? m/s (b) ...
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

You are trying out for the position of place-kicker on a professional football team. With the ball teed 50.0 m from the goalposts with a crossbar 3.05 m off the ground, you kick the ball at 28 m/s and 31° above the horizontal. (a) Is the field goal attempt good? no yes (b...
*Wednesday, December 3, 2014 by Anonymous*

**physics**

A stretched string fixed at each end has a mass of 17 g and a length of 10.5 m. The tension in the string is 44.5 N. What is the vibration frequency for the third harmonic? Answer in Hz.
*Wednesday, December 3, 2014 by Mei*

**Physics**

The range of a cannonball fired horizontally from a cliff is equal to the height of the cliff. What is the direction of the velocity vector of the projectile as it strikes the ground? (Ignore any effects due to air resistance.) ° (below the horizontal)
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

Elephants communicate via infrasound, at frequencies as low as 11 Hz that can travel up to 9 km. The intensity of these sounds can reach 106 dB, measured a distance of 4 m from the source. a) Determine the intensity level in W/m2 of the infrasound at 4 m from the source. b) ...
*Wednesday, December 3, 2014 by Annie*

**Physics**

A projectile is fired into the air from the top of a cliff of height h = 186 m above a valley. Its initial velocity is v0 = 64.8 m/s at an angle θ = 59° above the horizontal. Where does the projectile land? (Ignore any effects due to air resistance.)
*Wednesday, December 3, 2014 by Anonymous*

**physics**

An airplane traveling at v = 152 m/s emits a sound of frequency 1850 Hz. At what frequency does a stationary listener hear the sound as the plane approaches? Use 340 m/s for the speed of the sound and answer in Hz.
*Wednesday, December 3, 2014 by Annie*

**physics**

A 60 kg worker pulls buckets of sand from height of 10 m using a pulley fixed to a wooden beam.While he is pulling a 20 kg bucket filled with sand he slips and falls down holding the rope.Assuming that the worker did not collide with bucket,find the velocity of the worker at ...
*Wednesday, December 3, 2014 by Diana*

**Physics**

A stone thrown horizontally from the top of a 18-m tower hits the ground at a point 18 m from the base of the tower. (Ignore any effects due to air resistance.) (a) Find the speed at which the stone was thrown. m/s (b) Find the speed of the stone just before it hits the ground...
*Wednesday, December 3, 2014 by Anonymous*

**physics**

two ball A&B each have a chrge of 30micro C are apart 5cm ,what force does thecharge A exert on the charge B .At what distance will the force will be halved ?
*Wednesday, December 3, 2014 by tesfay tecle*

**physics**

A small crack occurs at the base of a 15.0 m high dam. The effective crack area through which water leaves is 1.30 *10-3 m2
*Wednesday, December 3, 2014 by Anonymous*

**physics**

A cannon barrel is elevated at an angle of 45°. It fires a ball with a speed of 250 m/s. (For the following questions, ignore air resistance.) (a) What height does the ball reach? m (b) How long is the ball in the air? s (c) What is the horizontal range of the cannon? km
*Wednesday, December 3, 2014 by Anonymous*

**Physics**

a 10m long steel cable is lifting a 30 ton crate upward off a ship. If the cable streches by .5cm under these conditions, determine the radius of the steel cable. Young's modulus of steel :2x10raised to 9 Pa
*Wednesday, December 3, 2014 by Chelie*

**Physics**

An auditorium has dimensions 10m x 10m x 60m. How many moles of air fill this volume at STP? I'm stumped.
*Wednesday, December 3, 2014 by Greg*

**physics **

a car starts from rest it reaches a velocity of 12 m/s in 6 second. a. what is its acceleration ? b. if its acceleration remains the same what will be its velocity after 10 seconds?
*Wednesday, December 3, 2014 by jazzy mae*

**physics **

michael is driving his sports car at 30m/s when he sees a dog on the road he slams on the breaks and comes to a stop in 3.0 second what is the acceleration of michael car?
*Wednesday, December 3, 2014 by jazzy mae*

**physics **

The internal energy of a system changes because the system gains 180 J of heat and performs 338 J of work. In returning to its initial state, the system loses 111 J of heat. During this return process, what work is involved? If the work is done by the system, then give the ...
*Wednesday, December 3, 2014 by S*

**physics**

A fire helicopter carries a 565 kg bucket at the end of a 16.7 m long cable. When the helicopter is returning from a fire at a constant speed of 22.5 m/s, the cable makes an angle of 20.5 ◦ with respect to the vertical. Find the horizontal force exerted by air resistance...
*Wednesday, December 3, 2014 by Anonymous*

**Calc Physics**

Geologists place tiltmeters on the sides of volcanoes to measure the displacement of the surface as magma moves inside the volcano. Although most tiltmeters today are electronic, the traditional tiltmeter, used for decades, consisted of two or more water-filled metal cans ...
*Wednesday, December 3, 2014 by Dib*

**physics**

A 0.80-m aluminium bar is held with its length parallel to the east-west direction and dropped from a bridge. Just before the bar hits the river below, its speed is 22 m/s, and the emf induced across its length is 5 X 10-4 V. Assuming the horizontal component of the earth'...
*Tuesday, December 2, 2014 by talemi*

**Physics Quick**

Quick question because i am trying to complete a lab report. How can i find the linear tangential acceleration of a wheel as it is turned by two hanging masses by using Newton's Second Law and the equation ΣT=Iα?
*Tuesday, December 2, 2014 by Dib*

**physics**

An object of mass m has an elastic collision with another object initially at rest, and continues to move in original direction but with one-third its original speed. What is the mass of the other object in terms of m?
*Tuesday, December 2, 2014 by SR485*

**physics**

a proton is projected perpendicularly into a magntic field that has a magnitude of 0.05T. the field is then adjusted so that an electron will follow a circular path of the same radius when it is projected perpendicularly
*Tuesday, December 2, 2014 by talemi*

**physics**

how do you solve 3x^4 + 11x^3=4x^2
*Tuesday, December 2, 2014 by john*

**Physics**

Quick question because i am trying to complete a lab report. How can i find the linear tangential acceleration of a wheel as it is turned by two hanging masses by using Newton's Second Law and the equation ΣT=Iα?
*Tuesday, December 2, 2014 by Dib*

**Physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*Tuesday, December 2, 2014 by Anonymous*

**physics**

Two blocks with masses m1 = 1.20 kg and m2 = 2.90 kg are connected by a massless string, as shown in the Figure. They are released from rest. The coefficent of kinetic friction between the upper block and the surface is 0.300. Assume that the pulley has a negligible mass and ...
*Tuesday, December 2, 2014 by Anonymous*

**physics**

Joyce and Efua are skating. Joyce pushes Efua, whose mass is 40.0 kg, with a force of 5.0 N. What is Efua's Resulting acceleration?
*Tuesday, December 2, 2014 by bleh*

**physics**

A man weighs 750.0 N on Earth at what altitude will he weigh 187.5 N?
*Tuesday, December 2, 2014 by moooose*

**physics **

The mass of a pendulum moves a total horizontal distance of 14cm in one cycle. What is the amplitude of the vibration?
*Tuesday, December 2, 2014 by kai*

**physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*Tuesday, December 2, 2014 by Anonymous*

**Physics**

A catapult on a cliff launches a large round rock towards a ship on the ocean below. The rock leaves the catapult from a height H of 32.0 m above sea level, directed at an angle θ above the horizontal with an unknown speed v0. The projectile remains in flight for 6.00 ...
*Tuesday, December 2, 2014 by Anonymous*

**Physics**

A proposed space station includes living quarters in a circular ring 50.5 m in diameter. At what angular speed should the ring rotate so the occupants feel that they have the same weight as they do on Earth?
*Tuesday, December 2, 2014 by Anonymous*

**Physics**

Two blocks with masses m1 = 1.20 kg and m2 = 2.90 kg are connected by a massless string, as shown in the Figure. They are released from rest. The coefficent of kinetic friction between the upper block and the surface is 0.300. Assume that the pulley has a negligible mass and ...
*Tuesday, December 2, 2014 by Anonymous*

**Physics**

A box of mass 10.9 kg with an initial velocity of 2.01 m/s slides down a plane, inclined at 38◦ with respect to the horizontal. The coefficient of kinetic friction is 1. The box stops after sliding a distance x. The acceleration due to gravity is 9.8 m/s. a. How far does...
*Tuesday, December 2, 2014 by Unknown*

**Physics**

A 284 kg crate is pulled along a level surface by an engine. The coefficient of kinetic friction between the crate and the surface is 0.513. How much power must the engine deliver to move the crate at a constant speed of 7.2 m/s?
*Tuesday, December 2, 2014 by Unknown*

**Physics**

A plastic bag is filled with nitrogen at atmospheric pressure and 22.0 oC. Assume that the mass of the bag is negligible and take the temperature of the outside air to be 0 oC. With the help of this "balloon" we want to lift a 50.0 kg girl off her feet. How large a ...
*Tuesday, December 2, 2014 by Anonymous*

**Physics**

An ultrasound pulse from a boat is directed at the sea floor. Ultrasound travels at 1400 m/s. The pulse take 0.5 seconds to return to the boat. What is the depth of the sea in this area?
*Tuesday, December 2, 2014 by Tas*

**Physics**

A cannon barrel is elevated at an angle of 45°. It fires a ball with a speed of 250 m/s. (For the following questions, ignore air resistance.) (a) What height does the ball reach? m (b) How long is the ball in the air? s (c) What is the horizontal range of the cannon? kmp
*Tuesday, December 2, 2014 by Anonymous*

**physics**

A 500kg roller coaster starts from rest at points 35m above the ground level. The car drives down into a valley 4m above the ground and then climbs the top of a hill that is 24m above the ground level. What is the velocity of the car in the valley and at the top of the hill? (...
*Tuesday, December 2, 2014 by cesa*

**physics**

A 6 N box is projected with a velocity of 2 m/s at the bottom of the plane inclined 30 degrees above the horizontal. If friction is neglected, how high up along the plane will it travel before coming to rest?
*Tuesday, December 2, 2014 by cesa*

**physics**

If someone is standing on an edge of a table with a book in his hand.if he is going to fall from the este then What should he do to avoid falling from edge?
*Tuesday, December 2, 2014 by aliya*

**Physics**

We always hear people say “You should conserve energy! Think of what will happen to the next generation if all our energy resources get depleted!” Is this in contradiction with the Law of Conservation of Energy which states that the total amount of energy in the ...
*Tuesday, December 2, 2014 by Brianna*