# Homework Help: Science: Physics

## Recent Homework Questions About Physics

**physics**

a force of 400 N at an angle of 15 degrees above horizontal is needed to pull a 180 kg trunk across the floor at constant speed. what is the coefficient of kinetic friction between the trunk and the floor

**Physics**

A force of 400 N at an angle of 15 degrees above the horizontal is needed to pull a 180 kg trunk across the floor at constant speed. What is the coefficient of kinetic friction between the trunk and the floor?

**Physics**

1. The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes 0.53 s for it to reach the floor. What is the mass m of the block on the left? There is no friction or mass in the pulley, and the connecting rope is very light. A) 16 kg B) 14 kg...

**Physics**

A tennis ball is released at 30 degrees. It reaches max height of 20 ft find initial speed

**Physics**

Two point sources emit sound waves of 1 m wavelength. The sources are pointed at each other. The sources, 2 m apart, emit waves which are in phase with each other at the instant of emission. a) Where, along the line between the sources are the waves out of phase with each ...

**Physics**

if a molecules in a solid has a temp of T = hf/2k then what would be the average energy of vibration 1) 0.88kT 2) 0.47kT 3) 0.62kT 4) 0.31kT

**Physics**

if a molecules in a solid has a temp of T = hf/2k then what would be the average energy of vibration

**Physics**

A solid weighs 6.4 kg in air and 5.6 in water. Find the density of the solid

**Physics**

A child is playing with a remote-controlled racecar on the fire escape of a sixth-floor apartment. An accidental turn sends the car through the railing and over the edge of the fire escape. Explain why the time it takes for the car to fall does not depend on the speed the ...

**physics**

A wheel starting from rest is uniformly accelerated with alpha=4 rad/seconds square for 10 seconds. It is then allowed to rotate uniformly for the next two seconds and is finally brought to rest in the next 10 seconds. Find the total angle rotated by the wheel

**physics forces/kinematic**

What does it mean that 1) A body can have zero acceleration but still in motion. 2) A body can have zero velocity but it's also accelerating. I don't really understand this two points, please explain it to me, thks!

**Physics**

Is screw a modified inclined plane?

**physics**

The coefficient of kinetic friction for wood on wood is o.55. The coefficient of kinetic friction for wood on wood is 0.68. For a 3.5kg wood block being pulled horizontally: a. what is the pull force needed to start the wood block moving on a wood floor? b. how hard would you ...

**Physics**

A non-homogeneous trunk, 5 meters long and 100 kilograms mass is in equilibrium and is hung at the ends by two strings; One form an angle of 37 degrees and the other an angle of 53 degrees, both with the horizontal. Determine the location of the center of mass of the trunk and...

**Physics**

A cheeta can run with a speed of 29 m/s. Determine the distance travelled by a running cheetah in 8.6 s. D= 29/8.6 = 3.3s

**Physics. I'd appreciate your help.**

A 33-N force acing due north and a 44-N force acting at 30 degrees act concurrently on point P. What is the magnitude and direction of a third force that produces equilibrium at point P?

**Physics**

A shopper exerts a force on a cart of 64N at an angle of 30° below the horizontal. a.) How much force pushes the cart in a forward direction? b.) How much force pushes the cart against the floor?

**Physics**

An ice skater with a mass of 60.0kg is moving at 20.0 m/s coasts to a halt in 2.00×10^2m on a smooth ice surface. What is the coefficient of friction between the ice and the skates?

**Physics**

A row of seats is parallel to a stage at a distance of 8.70 m from it. At the center and front of the stage is a diffraction horn loudspeaker that has a width of 7.50 cm. The speaker is playing a tone at a frequency of 9600 Hz . The speed of sound is 344 m/s. a. What is the ...

**physics**

A golfer tees off and hits a golf ball at a speed of 31 m/s and at an angle of 35 degrees. What is the horizontal velocity component of the ball? Round the answer to the nearest tenth of a m/s.

**work and energy PHYSICS**

A particle is projected vertically upwards from a point O on horizontal ground which reaches the maximum height Q. What is the energy associated at O and Q?

**Physics**

What is the work done when a force of 30Newtons moves through a distance of 20Meters?

**Physics**

The kiloton, which is used to measure the energy released in an atomic explosion, is equal to 4.2 ✕ 1012 J (approximately the energy released in the explosion of 1000 tons of TNT). Recalling that 1 kilocalorie of energy raises the temperature of 1 kg of water by 1°C and ...

**Physics**

The drawing shows a collision between two pucks on an air-hockey table. Puck A has a mass of 1.5 kg and is moving along the x axis with a velocity of +5.5 m/s. It makes a collision with puck B, which has a mass of 3.2 kg and is initially at rest. The collision is not head-on. ...

**Physics**

A space station, in the form of a wheel 197 m in diameter, rotates to provide an “artificial gravity” of 2.5 m/s2 for persons who walk around on the inner wall of the outer rim. The rate of the wheel’s rotation in revolutions per minute that will produce this effect is ...

**Physics - studying for finals**

(a) Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A = 5.00 cm, λ = 75.0 cm, f = 5.00 Hz, and y(0, t) = 0 at t = 0. (Use the following as necessary: x...

**Physics - studying for finals**

(a) Write the expression for y as a function of x and t in SI units for a sinusoidal wave traveling along a rope in the negative x direction with the following characteristics: A = 5.00 cm, λ = 75.0 cm, f = 5.00 Hz, and y(0, t) = 0 at t = 0. (Use the following as necessary: x...

**physics**

A 3.4 kg plant hangs from the bracket shown in the figure. The bracket has a mass of 0.65 kg , and its center of mass lies 9.0 cm from the wall. A single screw holds the bracket to the wall. Find the horizontal tension force in the screw. Hint: Imagine that the bracket is ...

**physics**

the terminal velocity of a tennis ball is about 21 m/s. a tennis ball is dropped from a hot air balloon. how fast will it be moving after falling for 10 s? 21m/s, 77m/s, 9.8m/s, or 98m/s.

**Physics**

Not sure where to begin with this question--any help appreciated! Two kids sitting on opposite sides of a small lake use sticks to beat the surface of the water at a frequency f=1.5 Hz. They notice that a standing wave pattern develops between the points where they are ...

**Physics**

If the torque required to loosen a nut that is holding a flat tire in place on a car has a magnitude of 31 N · m, what minimum force must be exerted by the mechanic at the end of a 24 cm-long wrench to loosen the nut? Answer in units of N

**physics**

experiencing a constant horizontal 1.10 m/s wind, a hot air balloon ascends from the launch site at a constant vertical speed of 2.70 m/s. at a height of 202 m, the balloonist maintains constant altitude for 10.3 s before releasing a small sandbag. how far from the launch site...

**Physics**

How many kilograms of water can be evaporated at 100 degrees Celsius by the combustion of 470 litres of fuel oil whose heat of combustion is 37 MJ/Litre

**PHYSICS**

A child (25 kg) walks along a 4 m plank of uniform density (m=8kg) that is laying with one end extending 1 m off the end of a dock. 1. Where is the ceanter of mass located in the plank? 2. What is the magnitude of the torque of the plank about the edge of the dock? 3. How far ...

**Physics**

You exert a force of 200 N at an angle of 15 degrees above horizontal to pull a 10 kg box across the floor at constant velocity. If the coefficient of kinetic friction between the box and the floor is 0.42, what is the acceleration of the box?

**Science physics**

How would the voltage output be affected if the armature is made to spin faster?

**physics**

A 1.6-kg block is attached to the end of a 2.0-m string to form a pendulum. The pendulum is released from rest when the string is horizontal. At the lowest point of its swing when it is moving horizontally, the block is hit by a 10-g bullet moving horizontally in the opposite ...

**Physics**

If 32s is required for an object to reach maximum height, what will be the time for an object to come back to its initial position? is it 32sec or -32 sec since it's traveling downwards???

**Physics**

In projectile motion the acceleration at the highest point of curved motion is___. a. 0 b. g c. undefined d. –g Which is true about an object was dropped from a 5 storey building? a. initial velocity is zero b. acceleration is equal to –g c. displacement is negative d. All...

**Physics**

How long does a car with an acceleration of 2.0 m/s2 take to go from 10 m/s to 30 m/s a. 3 m b. 6 m c. 18 m d. 36 m

**physics**

how much work is done if a force of 12N moves an object a distance of 5m

**Physics**

consider the circuit in the figure. find the current in the 13 ohm resistor. Answer in units of A

**Physics**

A child of mass 30 kg stands beside a circular platform of mass 95 kg and radius 2.4 m spinning at 2.3 rad/s. Treat the platform as a disk. The child steps on the rim. a) What is the new angular speed? b) She then walks to the center and stay there. What is the angular ...

**physics**

A half-cup of ice cream contains about 200 food Calories. How much power can be produced if the energy in a cup of ice cream is expended over a period of 10 minutes (600 seconds)? Each food Calorie is equal to 4,184 joules. Write your answer in watts and then in horsepower

**Physics**

Tarzan swings on a 33.0 m long vine initially inclined at an angle of 31.0◦ with the vertical. The acceleration of gravity if 9.81 m/s What is his speed at the bottom of the swing if he a) starts from rest? Answer in units of m/s b) pushes off with a speed of 5.00 m/s? ...

**Physics**

Please help! 1) While skiing in Jackson, Wyoming, your friend Ben (of mass 73.8 kg) started his descent down the bunny run, 23.9 m above the bottom of the run. If he started at rest and converted all of his gravitational potential energy into kinetic energy, what is Ben’s ...

**Physics**

I am really struggling with these two questions. Please help! 1)Two ice skaters approach each other at right angles. Skater A has a mass of 61.2 kg and travels in the +x direction at 2.25 m/s. Skater B has a mass of 66.2 kg and is moving in the +y direction at 1.3 m/s. They ...

**Physics**

A circular disk of mass 0.4 kg and radius 36 cm, initially not rotating, slips down a thin spindle onto a turntable (disk) of mass 1.7 kg and the same radius, rotating freely at 3.4 a) Find the new angular velocity of the combination; b) The change in the kinetic energy? c) If...

**Physics**

A 100 watts light bulb has an average life of 2000 hours. How much energy does it consume over its lifetime? The only thing I got was power=100 watts and time = 2000 hours but I need to convert to seconds and I don't kn how to do that.

**Physics**

You exert a horizontal force of 200 N to pull a 10-kg box across the floor. If the coefficient of kinetic friction between the box and the floor is .42, what is the acceleration of the box?

**Physics**

We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J into another system. What is the efficiency of the heat engine? (show you work)

**physics**

A hoop is at rest at the top of a 3.0 m long ramp with an angle of evelation of 24°. If the hoop rolls down the ramp, what is the final velocity of the hoop at the bottom of the ramp

**Physics**

A 775 kg roller coaster car is at the top of a roller coaster car is at the top of a roller coaster as shown below. The height of the car at point A is the minimum height that is necessary for the car to stay on the loop. The radius of the loop is 30 m. What is the height of ...

**physics**

A 873-kg (1930-lb) dragster, starting from rest completes a 403.6-m (0.2523-mile) run in 4.935 s. If the car had a constant acceleration, what would be its acceleration and final velocity?

**Physics**

How much heat energy is needed to change 0.25kg of water at 100°C to steam at 100°C? Show your work. Please don't give me the answer, I just need help figuring out how to find the answer. Thanks!

**Physics**

Chameleons catch insects with their tongues, which they can extend to great lengths at great speeds. A chameleon is aiming for an insect at a distance of 22 cm. The insect will sense the attack and move away 60 ms after it begins. In the first 60 ms, the chameleon’s tongue ...

**Physics**

To what potential a sphere of radius 10cm be charged so that the surface density of charge is equal to 1

**Physics**

How much heat does a freezer need to remove from 1kg of water at 40°C to make ice at 0°C? (You will need to use the specific heat of water to drop the temperature first, before trying to make the phase change!) Show your work. Please help! Also, this site isn't about giving ...

**Physics**

How much heat energy is needed to change 0.25kg of water at 100°C to steam at 100°C? Show your work. Please don't give me the answer, I just need help figuring out how to find the answer. Thanks!

**Physics**

The heat of fusion for water is 3.3 x 105 J/kg. How much heat energy is needed to can 3kg of ice at 0°C to water at 0°C? Show your work. Help please!! Don't give the answer, but please help me find the answer?! Thanks

**Physics**

Just as no mechanical device can be 100% efficient, no heat engine can transfer 100% of its heat to a single object. Some of the heat energy must be wasted (released into the environment). We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J ...

**physics**

Is the photoelectric effect a direct consequence of the wave character of E.M radiation or of the particle character of E.M radiation?

**PHYSICS**

Particles called mesons are produced by accelerator beams. if these particles travel at 2.70* 10^8 m/s and live 2.60*10^-8 s when at rest relative to an observee how long do they live as viewed in the laboratory?

**Physics**

A mango is dropped and falls freely from rest what are its position and velocity after 1.0s,2.0s, and 3.0s

**physics**

How much work is done in lifting a 300 Newton rock 10 meters from the ground?

**physics**

What is the time constant of a 10 H inductor and a 200 ohm resistor connected in series? Is my work correct? I did: T= L/R = 10 H divided by 200 ohm = 0.05 seconds = 50 milliseconds mS. Is that correct?

**Physics**

A bungee jumper runs off a platform and falls 40m before his bungee cord begins to stretch. Once the bungee cord begins to stretch his velocity slows by 20 m/s in 12m. If the mass of the bungee jumper is 55kg, what is the average force the bungee applies on him?

**Physics**

A 100 watts light bulb has an average life of 2000 hours. How much energy does it consume over its lifetime? The only thing I got was power=100 watts and time = 2000 hours but I need to convert to seconds and I don't kn how to do that.

**Physics!!!!!!**

A 0.18 kg baseball moving at +26 m/s is slowed to a stop by a catcher who exerts a constant force of −360 N. a) How long does it take this force to stop the ball? b) How far does the ball travel before stop- ping?

**physics**

In the circuit we have E=48V, R=6 ohm and L=4H. We close the switch at the instant t=0, the current I in the circuit grows from zero to its maximum value Io, and the permanent phase is established. A) determine the value of Io. B) calculate the values of the potential ...

**physics**

The self induced e.m.f created in a coil has the value of 24mV at the instant when the current is 4A and varies at the rate of 10A/s. What is the value of the self magnetic flux kn the coil at this instant?

**physics**

if copper rod has a length of 2m at 30 °C. what is its length at 70 °C ?

**physics**

the speed of sound in air at 0°C is 330m/s. at what temperature will the velocity of sound become 366m/s ?

**physics**

A wooden box, with a mass of 22 kg, is pulled at a constant speed with a rope that makes an angle of 25° with the wooden floor. What is the tension in the rope?

**Physics**

Your 2000 kg car is going 40 m/s on the highway when you see a police car up ahead. You apply the maximum 10000 N of brake force to slow your car down to the speed limit of 30 m/s. How many seconds will it take you to get down to the speed limit?

**physics**

A Syringe is filled with a solution of viscosity n=1.75x10^-3 pa s. The plunger of syringe has cross sectional area 9 x 10^-5 m^2. The needle has length 30mm and internal radius 3 x 10^-4 m. Intravenous pressure in patient is 2.0 kPa. What force must be applied to plunger of ...

**physics**

An electron beam is accelerated through 50kv potential difference and then passes through magnetic field produced by coils for 1cm the screen is located 10 cm from end is 50 cm wide.when the field is turned off the beam stikes the centre of screen.what field strength is ...

**Physics**

Hi, do you know how angular velocity relates to a "tight spiral" in football?

**physics**

A wire of length 60cm and mass 10kg is suspended by a pair of flexible leads in a magnetic field magnitude and direction of the current required to remove the tension in the supporting leads.

**physics**

A tuning fork is set into vibration above a vertical open tube filled with water. The water level is allowed to drop slowly. As it does so, the air in the tube above the water level is heard to resonate with the tuning fork when the distance from the tube opening to the water...

**physics**

An organ pipe is 81 cm long and at a temperature of 20 degrees C. What is the fundamental (in Hertz) if the pipe is closed at one end?

**physics**

A hiker determines the length of a lake by listening for the echo of her shout reflected by a cliff at the far end of the lake. She hears the echo 2.20 s after shouting. How long (in meters) is the lake?

**physics**

A guitar string is 97 cm long and has a mass of 3.6 g. The length L from the bridge to the support post is 61 cm, and the string is under a tension of 570 N. What is the frequency of the fundamental tone?

**physics**

A rope of mass 0.73 kg is stretched between two supports 31 m apart. If the tension in the rope is 1100.0 N, how long (in seconds) will it take a pulse to travel from one support to the other?

**General Physics II**

Hi, this is about thin film interference in ray optics. My book presents two similar problems, but somehow uses different paths for the same variable. I'll list out the given variables: --Problem A-- n1 < nf > n2, delta phase is therefore lambda over two. Film thickness ...

**Physics**

A 55.0 kg diver steps off a diving board and drops straight down into the water. The water provides an upward average net force 1480 N. If the diver comes to rest 5.6 m below the water's surface, what is the total distance between the diving board and the diver's stopping ...

**Physics**

We have a heat engine that produces 150 J of heat, does 40 J of work, and emits 110 J into another system. What is the efficiency of the heat engine? Please don't give me the answer! Just help figure out how to find it! The description for the lesson with this question was 1 ...

**Physics**

ou build a loop-the-loop in your backyard. It has a diameter of 3.10 m. a) How fast will you have to be moving at the top of the loop to avoid falling off? b)If you'll be coasting from the time you get to the bottom of the loop, how fast will you have to be going at the bottom?

**Physics**

Two identical racing horses go around a semicircular turn in a racecourse. The horses have the same speed, but horse A is on the inner side while horse B is on the outer side of the circular turn. Which horse has the greater acceleration while in the turn?

**Science Physics**

I don't understand how I would know what would happen if it collided or bounced, etc. How do I solve a question like this? Suppose the total momentum of two masses before collision is 100kg m/s. What is the total momentum of the two masses after they collide? 0 kg m/s 50 k m/s...

**Physics**

Kate (m = 50 kg) is swinging on a tire tied by a (light) rope (L = 3 m) to a tree limb. Her twin Ashley comes along and squeezes into the tire with her. Assume that at all times the centre of mass of the person(s) riding the tire is at the end of the rope. a) What was the ...

**Physics**

A mass (0.5 kg) and spring (k = 250 N/m) system oscillates with an amplitude of 3.5 cm. a) What is the total mechanical energy of the system? b) What is the maximum speed of the mass? c) What is the maximum acceleration of the mass? I need help please. What equation should I ...

**Physics**

A 0.5 kg air-track car is attached to the end of a horizontal spring of constant k = 20 N/m. The car is displaced 15 cm from its equilibrium point and released. a) What is the car's maximum speed? b) What is the car's maximum acceleration? c) What is the frequency f of the car...

**Physics**

A 200kg wagon is pushed along a horizontal surface at a constant 10m/s when it is released. After rolling a distance of 45m the wagon comes to a complete stop. Find the coefficient of friction.

**Physics**

A 15 kg box is given an initial push to start it moving up a frictionless ramp with angle theta = 30 degree and length delta r = 22m. What horizontal force F will keep the box moving with constant speed to the top of the ramp?

**Physics**

A ball having a weight of 1.5 N is dropped from a height of 4 meters. (Neglect air friction.) How much mechanical energy is "lost" just before it hits the ground?

**Physics!!!!!!**

In a scene in an action movie, a stunt man jumps from the top of one building to the top of another building 5.0 m away. After a running start, he leaps at an angle of 10◦ with respect to the flat roof while traveling at a speed of 5.6 m/s. The acceleration of gravity is 9....

**Physics**

(a) If the wavelength of an electron is 5.37 ✕ 10−7 m, how fast is it moving? (b) If the electron has a speed equal to 3.80 ✕ 106 m/s, what is its wavelength? What equation should I use?

**physics**

A daredevil is shot out of a cannon at 49.7◦ to the horizontal with an initial speed of 29.9 m/s. A net is positioned at a horizontal dis- tance of 49.8 m from the cannon from which the daredevil is shot. The acceleration of gravity is 9.81 m/s2 . At what height above the ...

**physics**

In a scene in an action movie, a stunt man jumps from the top of one building to the top of another building 4.4 m away. After a unning start, he leaps at an angle of 17◦ with respect to the flat roof while traveling at a speed of 4.3 m/s. The acceleration of gravity is 9.81...