# Homework Help: Science: Physics

## Recent Homework Questions About Physics

physics
a boat heads directly across a river with a speed through the water 8m/s. the river current is 2m/s a. what is the magnitude and direction of the boat velocity relative to the earth? b.when the boat reaches the other bank, how far will it be?

Physics
The speed of sound in a classroom is 343m/s. A) A tuning fork of frequency 512Hz is struck. What length of open air tube is required to create a resonant sound at the 1st harmonic? wavelength=v/f=343/512=0.67m L=.5wavelength=.5(.67)= 0.335m B) Fore the same tube, what tuning ...

Physics 11
As water waves from the ocean approach a shallow beach, their wavelengths become shorter. Explain why. v=fwavelength, frequency remains constant & velocity & wavelength decrease or increase w/ water depth. Is that a reasonable answer or are they looking for something else? ...

Physics 11
The speed of water waves is 30cm/s in deep water & 15cm/s in shallow water. If the wavelength in deep water is 1.0cm, what is the wavelength in shallow water? (v2/v1)=(wavelength2/wavelength1) Therefore (15/30)=(wavelength2/1) - 15=30wavlength2 -Wavelength2=0.5cm/s A) Is that ...

Physics !! Help Needed UrGeNtLy!!
A toddler applies a 25.0 N force to a chair over a distance of 2.5 m, the chair is being pushed across a smooth floor against a force of friction (10.0 N resistance). How much work is being done?

Physics
A child leaves her book bag on a slide. The bag, which is at the top of the slide, starts from rest and reaches the bottom in 1.63 s. The mass of the book bag is 2.55 kg, the length of the slide is 2.90 m and the angle of incline is 35.0°. (Assume the +x-axis to be parallel ...

Physics
A toddler applies a 25.0 N force to a chair over a distance of 2.5 m, the chair is being pushed across a smooth floor against a force of friction (10.0 N resistance). How much work is being done?

Physics
A satellite is orbiting a distant planet of mass 9.6e25 kg and radius 86700 km. The satellite orbits at a height of 8610 km above the surface of the planet. a) Determine the acceleration due to gravity at the location of the satellite orbit. b) Determine the velocity of the ...

Physics
A piece of copper ball of mass 20g at 200°c is placed in a copper calomiter of mass 60g containing 50g of water at 30°c ignoring heat losses.calculate the final steady temperature of the mixture

Physics
An object starting from rest travels 20m in first 2 seconds. What will be the distance covered by it in next 4 seconds

Physics
A 0.59g mass of Glynnium goes through a nuclear fission reaction. The energy from the process is used to lift a 97211kg Saturn 5 rocket into orbit. If the mass is transformed with 1% efficiency, what height does the rocket reach? Express your answer in kilometers

physics
An observer on Earth sees an alien vessel approach at a speed of 0.44c. The Enterprise comes to the rescue, overtaking the aliens while moving directly toward Earth at a speed of 0.89c relative to Earth. What is the speed of one vessel as seen by the other?

Physics
A charge of 5.00 ✕ 10^-9 C and a charge of -3.50 ✕ 10^-9 C are separated by a distance of 60.0 cm. Find the position at which a third charge, of 14.0 ✕ 10^-9 C, can be placed so that the net electrostatic force on it is zero.

physics
A detective is investigating a scene of an accident. He measures the length of an automobile's skid marks to find out how fast the automobile was going at the very beginning of the skid. Express In terms of V ( speed), L ( length) and any other suitable variables related to ...

physics
A cargo aircraft has taken off from a mountain. It is climbing at constant speed and at an angle of θ=37 above horizontal. The engines of the plane provide a thrust of F thrust =400kN and the wings provides a lift of F lift=756kN. Drag/air resistance is negligible so F thrust...

physics
The angle of incidence when the angle between the incident ray and refracted ray is 80 degrees is......

physics
lighted matchstick brought near the negatively charged electroscope

physics
A heavy metal beam AB of mass 25Kg is supported at its ends.The beam carries a mass of 150Kg at a distance of 0.75m from end A.If the beam is 2m long, determine the thrust A and B.

physics
A rocket expels gas at the rate of 0.5kg/s.If the force produced by the rocket is 100N,what is the velocity with which the gas is expelled.

physics
a heavy rod AB of length of 5m weighs 50N.The bar is supported in a horizontal position by two vertical strings X and Y.If string X is 0.6m from B and string Y is 1.8 from A,find the tension in the strings.

Physics, fluid mechanics
The temperature of earth atmosphere drops 5°C for every 1km elevation above the earth surface. If the air temperature at ground level is 15°C and 760 mmHg, determine the elevation in m when the pressure is 380 mmHg. Assume the air is an ideal gas with molecular weight of 29 ...

physics
An iron vise falls from rest at a great height. Neglecting air resistance, what is its speed after it has fallen for 5 seconds?

Physics
What is a fatigue fracture

Physics 11
Waves travelling along a string have a wavelength of 2.4m. When the waves reach the fixed end of the string, they are reflected to produce a standing wave pattern. How far from the end are the first 2 antinodes? I know that each wavelength has 2 antinodes so each antinode has ...

physics
a man can row a boat at 5km/hr. in still water and waits to cross a river to a position exactly opposite his starting point. If the river is 5km wide and is flowing at 4km/hr. eastwards find by scale drawing the direction in which he must set off in order to accomplish his ...

physics
A ball is thrown vertically upwards with a velocity of 2 m/s. It is seen at height h twice. Find the sum of the times, measured in seconds from the moment the ball is thrown, at which it is seen at height h. Take g=10m/s² Neglect air resistance.

physics , math
The hydrostatic equation holds not just for air, but for other fluids such as water (air, though it is a gas, is often referred to as a 'fluid') as well. In the case of water the equation becomes even easier, as water (as opposed to air) can be treated as incompressible, ...

physics
A heavy uniform bar is carried by two men on their shoulders. The weight of the bar is W. If one man lets it fall from the end carried by him, what will be the weight experienced by the other? A.W B.W/2 C.W/4 D.0 Could someone help me get through this problem?

physics
an x ray tube operate at 20kv and the current through it is 5mA. determine 1 number of electrons striking the target per second 2 the speed of electrons when they hit the target

physics
A car is traveling at 33.0 m/s  when the driver uses the brakes to slow down to 29.0 m/s in 2.50 seconds.   How many meters will it travel during that time

College Physics
a) The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/day for males. Express this quantity in ?g/s. Express this quantity in b) For adults, the RDA of the amino acid lysine is 12 mg per kg of body weight. How many grams per day should a 75 kg adult ...

Physics
a) The recommended daily allowance (RDA) of the trace metal magnesium is 410 mg/day for males. Express this quantity in ?g/s. Express this quantity in b) For adults, the RDA of the amino acid lysine is 12 mg per kg of body weight. How many grams per day should a 75 kg adult ...

Physics
A 5 m, 10 kg seesaw is balanced by a little girl(25 kg) and her father(80 kg) at the extreme opposite ends. How far from the seesaw's center of mass must the fulcrum be placed

Physics 11
Waves traveling along a string have a wavelength of 2.4m. When the waves reach the fixed end of the string, they are reflected to produce a standing wave pattern. How far from the end are the first 2 antinodes? I feel like I don't have enough info here... I know that 1 ...

Physics
Hello, I am wondering if someone can answer me this question: In an Atwood machine why do the tensions that handle both bodies are the same? (English is not my native language)

Physics
A 30-W led bulb and a 90-W led bulb are wired in the parallel to a 120-V source. You plug in a third bulb in parallel with the other two and the current increases to a 4.5-A, what is the wattage of the bulb you added? Please explain how you got the answer in steps.

Physics 11
A single wave pulse is sent along a thick rope that's tied to a thin rope, which in turn is attached to a wall. Reflection of the wave will occur at both points A (where the thick rope is attached to the thin rope) & point B (where the thin rope is attached to the wall) Which ...

Physics 11
2 men are fishing from small boats located 36m apart. Waves pass through the water, & each man's boat bobs up & down 15 times in 75s. At a time when 1 boat is on a crest, the other 1 is in a trough, & there is 1 crest between the 2 boats. f=15/75=.2Hz Wavelength=36m V=f(...

Physics
A basketball player who is 2.00 m tall is standing on the floor 8 m from the basket. If he shoots the ball at a 390 angle with the horizontal, what initial speed must he shoot the ball so that it goes through the hoop without striking the blackboard. The basket height is 3.05 m.

Physics
A basketball player who is 2.00 m tall is standing on the floor 8 m from the basket. If he shoots the ball at a 390 angle with the horizontal, what initial speed must he shoot the ball so that it goes through the hoop without striking the blackboard. The basket height is 3.05 m.

Physics
Juan throws a baseball with an initial speed of 40 m/s at an angle of 56 0 above the horizontal. Richard catches the ball at the same height that Juan threw it. How far did Juan throw the ball?

Physics
A ball rolls without slipping at 5 m/s off an incline of 15 degrees. The ball falls off the incline and enters a hole 4 meters below the incline. What is the horizontal distance between the bottom of the incline and the the hole. I havent the foggiest how to start.

Physics
For safety reasons, park rangers decide to start an avalanche on a mountain slope. They fire an artillery shell at an angle of 430 above the horizontal with an initial speed of 284 m/s. Thirty seconds later they see the explosion. What is the x coordinates of the shell where ...

physics
a cube of side 6cm is placed in graduated measuring cylinder 20 ml of watercis then added and the cubes remains at the bottom of the cylinder what will be calculated amount

physics
A climber is climbing a mountain. He is hanging from the bottom of a pair of anchors forming a Y shape at an angle θ. What is the force F at each anchor, express symbolically ( in terms of L(the climber), and θ)

physics
A climber is climbing a mountain. He is hanging from the bottom of a pair of anchors forming a Y shape at an angle θ. What is the force F at each anchor, express symbolically ( in terms of L, the climber, and θ)

Physics
The relative density of an alloy is 6.5.a.find the mass of a solid cube of side 20cm.b.what volume of the alloy has a mass of 13kg

Physics
Let vector A = (6.0 m, 300 south of east), vector B = (13.9 m, north), vector C = (5.0 m, 450 south of west).  Find the magnitude of vector D = A+B+C?

Physics 11
You are creating waves in a rope by shaking your hand back & forth. W/out changing the distance your hand moves, you begin to shake it faster & faster. What happens to each of the following aspects of the wave? Amplitude remains the same as the distance shaken remained the ...

Physics
A man of mass70Kg climbs a ladder which is 4m long leaning against a wall which is 3m high.Calculate the work done by this man

Physics 11
An FM radio station transmits radio signals that have a wavelength of 3.2m. Where would you have to adjust your tuner in order to pick up its music? Note: FM waves are measured in MHZ I have no idea where to go with this... Thank you :)

Physics
Four 6.5-kg spheres are located at the corners of a square of side 0.70 m . Calculate the magnitude of the gravitational force exerted on one sphere by the other three. Calculate the direction of the gravitational force exerted on one sphere by the other three.

Physics
due to conservation of mass, potential energy should always equal to kinetic energy. one possible reason the calculation for kinetic energy might be less than potential energy is _

Physics
How much time is needed to produce 840 joules of work if 100 watts of power is used?

Physics
A marble is flicked straight up. It takes 2.3 seconds to reach its maximum height. How long does it take it to return to its original height. Assume there is no air resistance totally lost. if i had velocity, or some other variable i would know what to do. all i know is travel...

Physics
A weightlifter raises a barbell of mass 150 kg from the floor to over his head 2.5 meters in 3 seconds. What is his average power input?

Physics
A baseball traveling upward passes a window 29.0 m above the street with a vertical speed of 14.0 m/s. If the ball was thrown from street level, what is the maximum height that the baseball reaches? Im stumped, please tell me what equations to use as well as what each variable...

physics
A baseball traveling upward passes a window 29.0 m above the street with a vertical speed of 14.0 m/s. If the ball was thrown from street level, what is the maximum height that the baseball reaches? im completely stumped, this is a cram semester and my professor is breifly ...

physics
A block of mass m is pressed against a vertical wall with a force F acting at an angle theta. What are the maximum and minimum forces of F that can be applied and still have the block remain stationary?

physics
Block A (mass = 3 kg), moving at +5 meters per second, collides with stationary block B (mass = 4 kg). Block A comes to a sudden stop, while block B starts moving. What will be the approximate final speed of block B?

Physics
A body vibrates in simple harmonic motion with an amplitude of 5 cm and a frequency of 0.50 Hz. a) Calculate: i) the maximum acceleration ii) the maximum velocity iii) the magnitude of the acceleration and velocity when the body is displaced 10 mm from its equilibrium position...

Physics
The piston in a particular car engine moves in approximately simple harmonic motion with an amplitude of 8 cm. The mass of the piston is 8 kg and the piston makes 100 oscillations per second. Calculate: a) the maximum value if the acceleration of the piston. b) the force ...

physics
A gallon of paint will cover 300 ft2. How many gallons will you need to paint a 12-ft x 18-ft wall with two coats of this paint? (Round to nearest half gallon

physics
Two books are stacked on top of each other. Book 1 is on top of Book 2. Book 1 has a string attached to it. The string is connected to the wall. The wall is to the left of the stacked Books. Book 2 is pulled to the right with a force F big enough to move Book 2. All surfaces ...

physics
There is a van that is being pushed by a car. The car is pushing the van from the van's behind. The van's mass is 4M and the car's mass is M. If the max force that the ground can provide to the car's tires is F, then what are the max forces between the car and the van? . ...

Math
In a class of 156 students who took maths and physics they all passed at leat 1 subject 75 pass math and physics.if twice has passed physics find how many students pass math only. Represent in Venn diagram.

Physics
1.A student repeatedly measured the length of a simple pendulum and recorded the results in centimetre as: 36.9, 36.7, 36.8 and 36.6. What is the precision index of this measurement in cm? 0.108 36.75 0.054 0.0269 2 How would the final result of the repeated measurement of the...

physics
the sum of magnitudes of two forces acting at a point is 18n and the magnitude of their resultant is 12n. if the resultant makes an angle of 90 degree with the force of smaller magnitude,what are the magnitude of two forces

Physics
A solenoid has 2000turns wound over a length of .3m Its cross sectional area is .0012(m)(m).around its central section a coil of 300 turns is wound .If an initial current of 2 amp flow in solenoid is reversed in .25sec. The emf induced in CPI will be what?

Physics
The speed of the boat on still water is 100km/h. The water flows from the west at a speed of 45km/h. In which direction must the sailor steer the boat in order to fly due to north? *What I don't understand is 'which way(direction) is the boat travelling?' Thanks in advance.

physics
A box is pushed along a surface with constant horizontal force. The surface is frictionless. The box starts from rest and travels 6.0m in 2.0s. if the experiment is repeated but with the box's mass doubled, how far will it travel?

PHYSICS!
Find the gauge pressure in pascals in a soap bubble 0.04 m in diameter. The surface tension is 25.0 x 10^4 Pa.

PHYSICS!
The piston of hydraulic automobile lift is 0.30 m in diameter. Calculate the gauge pressure required to lift a car with a mass 1000 kg in, A) Pascals B) Atm

PHYSICS!
At a certain point in a pipeline the water's speed is 4.00 m/s and the gauge pressure is 5.00 x 10^4 Pa. Find the gauge pressure at a second point in the line, 12.0 m lower than the first, if the cross-section area at the second point is twice that at the first.

PHYSICS!
An ore sample weighs 15.00 N in air. When the sample is suspended by a light cord and totally immersed in water, the tension in the cord is 9.00 N. Find the total volume and the density of the sample.

physics
a density bottle of capacity 50ml weighs 27g when empty and 90g when it is filled with glycerine. whatis the density of glycerine in kg/m^3?

Physics
A brown road runner is standing still pecking at soil looking for worms.  Suddenly, a black road runner travelling at a constant speed of 9.25 m/s, overtakes the brown roadrunner.   The brown road runner notices that the other one has a worm in its mouth and begins to ...

physics
1. The weight in the following diagram has a mass of 0.750 kg and the cart has a mass of 0.52 kg. There is a friction force of 2.1 N acting on the cart. What is the tension in the string? a. 4.4 N b. 4.3 N c. 4.1 N d. 4.2 N 2. An 8.5 kg block is attached to a weight. The ...

Physics
1. The weight in the following diagram has a mass of 0.750 kg and the cart has a mass of 0.52 kg. There is a friction force of 2.1 N acting on the cart. What is the tension in the string? a. 4.4 N b. 4.3 N c. 4.1 N d. 4.2 N 2. An 8.5 kg block is attached to a weight. The ...

physics
A large truck with a mass of 3200 kg is pulling a trailer with a mass of 2400 kg. Both are accelerating at a rate of 0.45 m/s^2 . Determine the tension force between the truck and the trailer, and determine the force with which the truck is pulling. I'm not sure how to find ...

Physics
A particle starts from rest and has an acceleration of 2m/s*2 for 10sec.After that, the particle travels for 30sec with constant speed and then undergoes a retardation of 4m/s*2 and comes back to rest. The total distance covered by the particle is?

Physics
Your electric jug element produces 1.5kW of power. What is the minimum time it will take to heat 1.5L of water from 20 degrees Celcius to boiling

Physics
Your vertical spring accelerometer has a 200 g mass hanging from it. You climb aboard the roller coaster and watch the accelerometer read 0.4 g for 3 seconds while descending and read 1.5 for 2 seconds while climbing the next peak. The car weighs 2000 kg. What is your ...

Physics
A ball is moving to and fro about the lowest point of a smooth hemispherical bowl. If it is able to rise up to a height of 45cm on either side.it's speed at the lowest point must be?

Physics
In relativistic regimes, the total energy of an object with rest mass, m, speed, v, is: a); (Gama)mc^2 B);squre root of (m^2c^4 + p^2c^2)

physics
calculate the ratio of momentum when 1.velocity of the object is doubled 2.mass of the object is halved?

Physics
a) Why do you think our eyes fail to see object clearly at varous distances? b) (i) Explain how image of an object is formed in the human eye (ii) What are ciliary muscles? Explain the function of these muscles c) Discuss the similarities and differences between the lens ...

Physics
A 0.5kg ball dropped from a height of 2.4 m above the floor. if an impact with the floor it loses 3 joules of energy, how high will it bounce?

Physics
Two positive charges of 0.2microC and 0.01 microC are placed 10cm apart. Calculate the work done in reducing their distance to 5 cm

physics/calculus
can someone explain to me why the derivative and second derivative of this position vector r=ax+bty is r'=ax' +by'+ bty' ( why is there a by'...?) and r''=ax'' + cy' +cy' +cty'' ( why is there 2 cy' 's?

physics
A pin 2 cm long is placed 12 cm away from a convex lens at right angles to the principal axis. If the focal length of the lens is 20 cm, by scale drawing and lens formula find the nature , size and position of image.

Physics 11
A student throws a .1kg ball at a wall. The ball hits the wall perpendicularly with a speed of 5m/s & then bounces back w/ a new speed of 4m/s. What impulse is given to the ball by the wall? I used deltaP= m deltaV so deltaP= .1*(-1) to get -.1N-s. I got it wrong! Can someone ...

Physics 11
A 1200Kg car travels at a constant speed of 26m/s for 5s up a 130m long hill. The total height of the hill is 27m & the friction force acting on the car is 2520N. What power was used by the car in traveling up the hill? I know that Fnet=o bc velocity is constant, therefore ...

Physics 11
If 2 vehicles are moving toward each other from opposite directions & are the same mass & velocity then momentum=0 correct? Because p=M1V1 - M1V1 Thanks!! :)

PHYSICS
the radius of the planet Venus is nearly the same as that of the earth.if an object weighs We on the earth,what is valu

Physics 11
A 62kg cyclist changes the speed of a 12kg bicycle from 8.2m/s to 12.7m/s. Determine the work done. I've already answered & gotten this question correct, however it made me confused about the concept. I found Ek. & Ek to find change in Ek which was 3479.85. He did work against...

Physics 11
In the absence of air resistance, a ball of mass m is tossed upward to reach a height of 20m. Given that Fg=mg, what is the net force on the ball at the 10m position (half way up)? a)2mg b)mg c)mg/4 d)mg/2 I already got this wrong bc I had no idea how to solve. I have a ...

Physics (Mirror Rays)
3. When an object is located very far away from a convex mirror, the image of the object is 18 cm behind the mirror. Using a ray diagram drawn to scale, determine where the image is located when the object is placed 9.0 cm in front of the mirror. Note that the mirror must be ...

physics
a man having a mass of 60 kg exerts a horizontal force of 200 newton in pushing a 90 kg object a distance of 60 meters along horizontal floor. he does this at constant velocity in 3 seconds.the weight of man will be?

physics
a ball of weight 200 grams,is tied to the end of a cord and whirled in a horizontal circle of radius 0.6 m.if the ball makes five complete revolutions in 2 seconds,what will be the linear speed of the ball?