# Homework Help: Science: Physics

## Recent Homework Questions About Physics

physics
A 1100-kg elevator is lifted at a constant speed of 1.5 m/s through a height of 20 m. Part A How much work is done by the tension in the elevator cable? Express your answer to two significant figures and include appropriate units. Part B How much work is done by gravity?

physics
A boy pulls a bag of baseball bats across a ball field toward the parking lot. The bag of bats has a mass of 6.8 kg, and the boy exerts a horizontal force of 20 N on the bag. As a result, the bag accelerates from rest to a speed of 1.12 m/s in a distance of 5.4 m. Part A What ...

Physics
A 100-W light bulb has an average lifetime of 800 h. how many electrons Move through the bulb in its life?

physics-optics
Light of wavelength 649nm illuminates two slits, which are 1.6mm apart. A fringe pattern appears on a screen 2.7m from the slits. What is the distance between dark fringe number 4 and dark fringe number 5?

physics-optics
Two speakers are separated by a distance of 3.4 m. A point P is placed at 5.7 m from one of the speakers so that they form a right triangle. If the speed of sound in this situation is 340 m/s and the speakers are in phase, what is the lowest frequency for which the intensity ...

physics-optics
Two narrow slits are 0.25mm apart. The dark fringe of order 55 is 0.8 degrees from the central bright fringe. What is the wavelength of the light?

physics-optics
In a Young's double-slit experiment, the slits are 0.4mm apart and are illuminated by laser light of wavelength 602.4nm. The screen is 3.1m away. What is the number of dark fringes per centimetre?

Physics
A cell of emf 2v and internal resistance of 1ohms passes a current through an external load of 9ohms.calculate the potential difference across the cell

AP Physics 1
This isnt exactly a hw question... but for anyone who knows: Im considering to take AP Physics next year as a challenge. I'm going to be taking pre-calc next year ( i already took my algebras) and im not too great in math but im good at memorizing and retaining info... will AP...

Physics-Graivty
Suppose planet earth suddenly grew in size, so that its radius was twice as large as before. Also suppose that at the same time, its mass also doubled to twice its former mass. If you weight used to be 700 N, what is it on this "new" Earth. Describe why this is the answer ...

Physics
A 100-W light bulb has an average lifetime of 800 h. how many electrons Move through the bulb in its life?

a meter rod is pivoted at the center 5kg body is attched 10cm from the one end 30cm from the pivot at the other side how much mass be connected to keep the meter in equilibrium

eqilibrium /physics
a rod 200cm long is pivoted at the 80cm from the one end 3kg body is attched at the one end 80cm away from the pivoted point how far from the other end 5kg body be attched to the rod

Physics
At what height above the earth's surface. the acceleration due to gravity will be 1/9th of its value at the earth's surface. Re = 6400km

physics
A car of mass 500kg and velocity=36km/h and suddenlybreak applied 150m calculate the force and work done?

physics
if f1= 3i + 5j + 6k and f2= 2i + 3j - 4k both measure the newton are displaced by d= 3i - 2j + 4k measure the metre, find the workdone

physics
A 6000kg truck travelling north at 5m/s collides with a 4000kg truck moving west at 15m/s,if the two trucks remain locked together after collision,find (a)with what speed and in what direction do they move immediately after collision?(b)what is the lost of kinetic energy of ...

physics
A ball is dropped from a height of 8m onto a horizontal floor and rebounds to a height of 12m.what is the coefficient of restitution between the ball and the floor?take g=10m/s^2

Physics
An object weighing 1N in air .it got 0.8N weight when it is emerssed in water what is it's loss of weight?

PHYSICS
Compare the electric force holding the electron in orbit (r=0.53Ã—10âˆ’10m) around the proton nucleus of the hydrogen atom, with the gravitational force between the same electron and proton. What is the ratio of these two forces?

PHYSICS
If that charge is 3.7 μC , by what percentage does the mass of a 31 g comb change during charging?

Physics
When an object of height 1cm is kept at a distance 4cm from a concave mirror,its erect image of height 1.5cm is formed at a distance 6cm behind the mirror.find the focallength of mirror,by drawing

Physics
A point light source is kept in front of a convex mirror at a distance of 40cm.find the position of image by drawing

Physics
An object 5cm high is placed at a distance 60cm in front of a concave mirror of focallength 10cm.find the position and size of the image by drawing.

Science, Physics
A particle moves through angular displacement ø on a circular path of radius r. The linear displacement will be

Physics
The number of revolution made by a fly wheel change from 300rpm to1500rpm in 10s.Calculate angular acceleration assuming it to be uniform .Also calculate the number of revolution made during the time?

Physics
A rocket speeding through space at 0.3c launches a small satellite. If the satellite is launched with its own velocity in the direction of the rocket’s motion at 0.4c, what will be the satellite’s observed velocity from the perspective of someone watching it from Earth?

physics
How long would it take a 750W electric motor to do 1.5x10^5 of work What I have so far: So we know w=fappxd 1.5x10^5=750xd So we can arrange that to find d. And then maybe use a formula to find t? Thank you!!

Physics
A. A 45kg gymnast launched herself from a vault with a speed of 1.8m/s.she lands upright on the ground 125 cm below at what speed will she hit the ground? B. On landing she bends her knees through a height of 0.15m. Detained the average force exerted by her legs during the ...

torque physics
a body of mass 5kg starts rotaing from rest on a circular track of radius 8m after 1mint it towards 5 rotations per30sec find the torque

Physics 109
An object executes circular motion with a constant speed whenever the net force on it acts perpendicular to its velocity. What happens to the speed if the force is not perpendicular?

Physics
A spherical body of diameter 4cm falls freely through air with the velocity of 0.5m/s. The coefficient of velocity of air is 2*10^-5Nm/m^2.find the viscous force acting on the body.

Physics
Find the terminal velocity of a raindrop of diameter 3mm when it fall through atmospheric air (Appointment and is 249.7m/s)

Physics
Water is pumped at 120m^3/min from a lake into a tank 35 m above the lake. (a) What power, in kW, must be delivered by the pump? (b) What is the increase in potential energy of the water each minute?

PHYSICS
A person with the weight of 691 N stands on a bathroom scale in a motionless elevator. The elevator begins to move and the scale momentarily changes to 499 N. (a) Draw a force diagram of the situation. (b) Create a qualitative vertical equation for this situation. (c) ...

physics
TWo identical l-5.0-kg balls, Figure P5.85 each 25.0 cm in diameter, are suspended by two 35.0-cm wires (Fig. P5.85). The entire apparatus is supported by a single 18.0-cm wire, and the surfaces oi the balls are perf'ectly smooth. (a) Find the tension in each of the three ...

physics
suppose a car is driven from town A to town B from town B to town C and from town C to town D which have equal distances at average speeds 20km/hr,60km/hr and 120km/hr respectively,what is the average speed for the whole journey

Physics
An air craft is traveling due north with avelocity of 100 m/s, astrong wind blows from the west with avelocity of 25m/s find resultant velocity

Physics
Two identical pucks are set on a collision course on an air table. After the collision, puck A has a final velocity of 5.00cm/s at an angle of 28 degrees from the vertical and puck B has a final velocity of 4.00cm/s at an angle of 32 degrees from the vertical. Determine the ...

physics
A steel wire is used to lift heavy object. The cable has a diameter of 14.25 mm and an initial length of 33.5 m. If the cable stretches 2.50 mm, what is the mass of the heavy object? Use 20.0 x 10^10 Pa for Young’s modulus for steel. Give your answer in kg and with 3 ...

Physics
In a simple machine, the energy input is 120j. If the efficiency of the machine is 80%. Calculate the energy output

Physics
A Micro –Hydro turbine generator rotor is accelerating uniformly from an angular velocity of 610 rpm to its operating angular velocity of 837 rpm. The radius of the rotor is 0.62 m and its rotational acceleration is 5.9 rad/s2. What is the rotor’s angular velocity (in rad/...

Physics
An pie plate of radius 0.12 m spins and accelerates at a constant rate of 13 rad/s. What was its angular acceleration? R=0.12. W1=13 W2=29 t=5.4 (29 -13) /5.4= 2.96rad/s is the answer I calc but the answer key had 2.8 rad/s

Physics
a . rather then taking the elevator a a 65kg student decided to climb 276m vertical height of stairs to the observation deck of the effiel tower. How much work does the student do against gravity climbing to this level? b. It's estimate that 1kg of fat will provide 3.8x10^7 J ...

physics
There are three charges on a line. Charge A has 6e-07 C and is located at x=0. Charge 1 has 2e-06 C and is located at x = 1 m. Charge B has -5e-05 C and is located at x = 4 m.

physics
An electron and a proton have charges of opposite sign, but the magnitude of their charges has the same value of 1.60 10-19 C. Suppose the electron and proton in a hydrogen atom are separated by a distance of 4.30 10-11 m. What are the magnitude and direction of the ...

physics
a stone attached to the end of elastic string is whirled around in a circular path of radius 20cm if the stone makes 15 complete revolution in 5 seconds, calculate its angular and linear velocities.

physics
There are two charged particles. They exert an electrostatic force of 10 N on each other. Suppose the distance between the two particles is increased to five times the original distance. What will the magnitude of the force?

Physics - Capacitance
In the case of having two plates of a capacitor, in the formula for capacitance C = (Epsilon)(A/d), is A the sum of the areas of each plate or just the area of one plate? And if it is the latter, then it can be assumed that both plates have the same area, right?

physics /torque
a door is fixed with the support the length of the door is 3.3foot. the handle is attached at o.3foot. from a side opposiite to the side of hinches. it is opened with the torque of 5Nm. how much force is needed

Physics
a boy whose weight is 600 N runs up a flight of stairs 10 m high in 12 second .What is his average power?

physics
Water has a specific heat of 4.186 J/g°C. How much heat is required to increase 10.0 g of water from 25.0°C to 30.0°C?

physics
a man weighs 162 pounds, and is 69 inches tall. his forearm is parallel to the ground. he holds an 8 pound weight in his hand. the biceps has an angle of insertion of 85 degrees with a distance of 1.4 inches at insertion. the system is equilibrium. what force is the biceps ...

Physics
A billiard ball 0.62 kg moving at 8.2 m/a elastically strikes a bowling ball, 3.2 kg moving in opposite direction at 1.2 m/s Calculate final velocities The kinetic energy before the collision The kinetic energy after the collision

physics
A playground merry-go-round of radius R = 1.1 m has a moment of inertia of I = 280 kg*m^2. and is rotating at a rate of ω = 9 rev/min around a frictionless vertical axis. Facing the axle, a 37 kg child hops onto the merry-go-round and manages to sit down on the edge. What is ...

physics
A 2.51 kg particle moves in the xy plane with a velocity of v = ( 4.98 , -3.58 ) m/s. Determine the angular momentum of the particle about the origin when its position vector is r = ( 1.73 , 1.15 ) m.

Physics
A uniform meter rule is balanced at the 30cm mark when a load of0.8 newtons is hung at the zero mark .at which point is the center of gravity.

Physics
Using Coulomb's law to solve: Charge A is +2.0x10^-6C and charge B is +3.0x10^-6C. The two changes are 3 m apart. What is the force between them?Is the force attractive or repulsive? Okay so here's what I have so far (2.0x10^-6)(3.0x10^-6)/(3)^2 It is confusing me with the ...

physics
a) a driver of mass 55kg needs to jump to a height of 1.1m above her take off height, at which point her speed needs to be 0.5m/s^. How fast just she be travelling the instant her feet leave the diving board? So we know eg=mgh =9.8*55*1.1 I assumed we're trying to find the ...

Physics
Determine the amount of work required for each of the following: a) to lower a 35kg sack of rice through a height of 3.5m b) to carry the 30kg sack of rice 10m along a corridor c)to crave the sack of rice 15m along the corridor at a constant velocity against a frictional force...

physics
Driving in your car with a constant speed of v= 22 m/s, you encounter a bump in the road that has a circular cross-section, as indicated in the figure (Figure 1) . Part A If the radius of curvature of the bump is 52 m, find the apparent weight of a 66-kg person in your car as ...

PHYSICS
Two springs, with force constants k1=175N/m and k2=270N/m, are connected in series, as shown in (Figure 1) . Part A: When a mass m=0.50kg is attached to the springs, what is the amount of stretch, x? k1 I k2 I m ? ] x

physics help
At a playground, a 20-kg child sits on a spinning merry-go-round, as shown from above in (Figure 1) . The merry-go-round completes one revolution every 6.2 s, and the child sits at a radius of r=1.8m. a) What is the force of static friction acting on the child? b) What is the ...

Physics
3 particles of masses m1 = 1.5 kg , m2 = 2.5 kg and m3 = 3.5 kg form an equilateral triangle of edge length l= 135 cm. Determine the center of mass of the system.

Physics
Max has a mass of 65 kg and sits in a canoe that has a mass of 55 kg. He jumps with a horizontal velocity of 2m/s towards the shore. What is the velocity of the canoe?

physics
A steel wire is used to lift heavy object. The cable has a diameter of 14.25 mm and an initial length of 33.5 m. If the cable stretches 2.50 mm, what is the mass of the heavy object? Use 20.0 x 1010 Pa for Young’s modulus for steel. Give your answer in kg and with 3 ...

Physics
A wheel mounted on a stationary axle starts at rest and is given the following angular acceleration: 9-12t where t is the time after the wheel begins to rotate. Find the number of revolutions that the wheel turns before it stops ( and begins to turn in the opposite direction).

Physics
A 0.250 kg ball swung on a 1.3 m string in a vertical circle. If it's tangential speed at the bottom of the path is 4.2 m/s, what is the maximum speed the ball can have at the top and still move in a circle?

Physics
What is the mass of water that has its temperature raised from 27°C to 32°C when it is heated by 5.0 x 106 J of heat energy?

Physics
Okay, I'm really confused in general. My question says: "A solid piece of clear transparent material has an index of refraction of 1.61. If you place it into a clear transparent solution and it seems to disappear, approximately what is the index of the refraction of the ...

Physics
In the figure, the meterstick's mass is 0.130 kg and the string tension is 2.30 N . The system is in equilibrium. A) Find the unknown mass m. B) Find the upward force the fulcrum exerts on the stick. I found part A and the answer is .634kg but I can not figure out part B.

Calc. Based Physics
10.1 Three uniform spheres with masses m1 = 6.0 kg, m2 = 2.0 kg , and m3 = 4.0 kg are fixed at the positions shown in the diagram. Assume they are completely isolated and there are no other masses nearby. m_1 | | 3cm | m_2-- P ^ | 1cm |2cm m_3 (a) What is the magnitude of the ...

PHYSICS
Two tugs are towing a ship at Constant speed against a total resistance of 50KN. The angles between the tow ropes and the direction of moment are 30degree and 60degree respectively. What is the tension in each of the tow ropes?

Physics
A 200h bag of potato chips contains 4.8MJ of energy. How long would it take you working at your maximum body power to consume this energy? So we did 2 trials where we ran up the stairs, and my final power for 1 was 246W and for the other it was 338W. So I assume you divide the...

Physics
How many calories are needed to heat 247 grams of ice at 14F to water at 50C? s(ice)=0.500kcal/kg/C, s(water)=1.000kcal/kg/C ,hf= 79.7kcal/kg, hv= 540 kcal/kg

physics help
Driving in your car with a constant speed of v= 22 m/s, you encounter a bump in the road that has a circular cross-section, as indicated in the figure. If the radius of curvature of the bump is 52 m, find the apparent weight of a 66-kg person in your car as you pass over the ...

physics
Two springs, with force constants k1=175N/m and k2=270N/m, are connected in series When a mass m=0.50kg is attached to the springs, what is the amount of stretch, x?

Physics
A train blows its horn as it approaches a crossing. A.) if the train engineer observes a frequency of 125Hz and a stationary observer at the crossing observes a frequency of 132Hz, what is the speed of the train? (The speed of sound is 330m/sec on this day). B.) what frequency...

Physics
Two resistors each of 15 Ohm and 10 Ohm are in parallel, find the effective resistance

Physics
Hello so my question is an 85kg kangaroo acquires 2.2kJ of energy in jumping straight up and down from rest. How high does the kangaroo jump? My solution: When he's at rest Eg=2200J but in air Eg=0 Eg=mhh 2200=85(9.8)h 2.64m=h Looking at it now it doesn't really make sense ...

Physics
A 240 kg roller coaster car Rolls over the crest of the roller coaster with a speed of 2.2m/s.if it falls through a vertical height of 12m down the tracks to the bottom of a trough, how fast will it be travelling? So here's what I did but I don't think it's right: Eg=mgh =...

physics
Consider a ladder placed against a frictionless wall. What happens to the friction force between the ladder and the floor as you climb up the ladder? (Assume the ladder is not sliding.) A. The friction force decreases. B. The friction force remains the same. C. The friction ...

physics
Which force(s) provide(s) the centripetal force needed for a car to make a turn on a banked curve? A. Weight, only B. Tension, only. C. Friction, only. D. Coriolis force, only. E. Friction and normal force. Is it D?

physics
determine the center of mass for three particles(1.5, 2.5, 3.5) forming a equilateral triangle one side lenght of 135cm.

physics
what is the work done in moving a positive charge 12UC across two points 6cm apart

AP physics (multiple choice)
an object is undergoing uniform circular motion. which of the following statements is true? a. the velocity is constant b. the acceleration is constant. c. the a is constant but v varies. d. the v is constant but the a varies. E. both a and v vary.

AP physics
1000 kg car is going clockwise around a curve iwth radius of 30m. coefficient of frction=0.5 if the road was banded at an angle what would happen to the speed required or the radius of the curve? explain.

Physics
A 55kg arrow is fired vertically upward at a speed of 42m/s. It rises upwards, then drops and lands on the ground. If it lodges itself 12cm in the ground, determine the average force that the ground exerts on the arrow This is what I've done but I don't think it's correct: Eg=...

physics
A stone of mass 5kg is thrown vertically upwards with velocity 10ms final calculate the height.

Physics
Efficiency of a single fixed pulley is 85%.what effort is needed to lift a load of 85kgf using it?

Physics 2
a point charge q1=+9μc is held fixed at the origin. A second point charge with a charge of-5μC and mass of 3.2 x 10^-4 kg is placed on the + x-axis, 0.90 m from the origin. a.) What is the potential energy of the pair of charges? (consider the potential to be zero at ...

physics
a uniform meter rule is pivoted at 20cm mark . It is balanced when mass of 100gm on 10cm mark and mass of 50 gm on 30 cm mark are suspended. Find d mass of meter rule

Physics - Voltage across a wire of unknown length
Four copper wires of equal length L are connected to a 100V source. Their cross-sectional area are 1cm^2, 2cm^2, 3cm^2, and 4cm^2. Find the voltage across the 3cm^2 wire. Leave your answer in terms of L, it should cancel out. - So I tried using and equating various relevant ...

physics
A block of mass m = 3.53 kg is attached to a spring which is resting on a horizontal frictionless table. The block is pushed into the spring, compressing it by 5.00 m, and is then released from rest. The spring begins to push the block back toward the equilibrium position at x...

physics
fluid of constant density = 960 kg/m3 is flowing steadily through the above tube. The radius at the sections are r1 = 0.05 m, r2 = 0.04 m. The gauge pressure at 1 is P1 = 200 000 Pa and the velocity here is v1 = 5 m/s. We want to know the gauge pressure at section 2.

physics
Driving in your car with a constant speed of v= 22 m/s, you encounter a bump in the road that has a circular cross-section, as indicated in the figure. If the radius of curvature of the bump is 52 m, find the apparent weight of a 66-kg person in your car as you pass over the ...

PHYSICS QUESTIONS
Two springs, with force constants k1=175N/m and k2=270N/m, are connected in series, as shown in (Figure 1) .When a mass m=0.50kg is attached to the springs, what is the amount of stretch, x?

physics
A water main with a radius of 0.15 m contains water with an average velocity of 3 m/s .What is the flow rate in the water main?

physics question
When you take your 1700-kg car out for a spin, you go around a corner of radius 55 m with a speed of 20 m/s. The coefficient of static friction between the car and the road is 0.88.Assuming your car doesn't skid, what is the force exerted on it by static friction?

PHYSICS
When a 8.88 kg mass is placed on top of a vertical spring, the spring compresses 4.54 cm . Part A Find the force constant of the spring. 8.88kg*9.81=87.1128 divided by4.54 =19.187N/CM 0.0001918784141 KN/M IS IT RIGHT? PLS HELP