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October 25, 2014

Homework Help: Science: Physics

Recent Homework Questions About Physics

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physics
If a nuclide has a decay constant of 10^-6 s-1 what is its half life ??? I think it is 0.693 / 10^-6 = 693000 or 6.93 x 10^5 Is this right ...
Wednesday, August 13, 2014 at 8:04am

Physics
Calculate the height through which a crane can lift a load of 4t , when its motor of 4HP operates for 10s. [Take g=10N/kg ]
Wednesday, August 13, 2014 at 3:25am

physics
You jog at 9.5 km/h for 7.0km , then you jump into a car and drive an additional 16km . With what average speed must you drive your car if your average speed for the entire 23km is to be 22 km/h? Work: i tried setting up a proportion and setting it to each other using the ...
Tuesday, August 12, 2014 at 7:31pm

High School Physics
A car is moving at 20.0 m/s [N] when it begins to constantly accelerate to a final velocity of 10.0 m/s [E]. The magnitude of its displacement during this time is 1.50 x 10^2 m. How long did the acceleration last? I know that the answer is 13.4 s, but can you show me how you ...
Tuesday, August 12, 2014 at 6:45pm

physics
according to the statement given what is the magnitude of the velocity of the rock just before it strikes the ground
Tuesday, August 12, 2014 at 2:46pm

physics
A man in a boat moving at constant speed of 60km/h relative to the shore throws an object in the forward direction with a speed of 30km/h. What is the speed of the object as measured by an observer at rest at the shore?
Tuesday, August 12, 2014 at 8:11am

physics
a block of mass 3 kg rests on a smooth table and connected to another block of mass 2 kg, after passing over and ideal pulley, the block of mass 2 kg is released. how long does it take the block to travel 80 cm
Tuesday, August 12, 2014 at 5:00am

physics
how to find the internal diameter of a straw?
Monday, August 11, 2014 at 8:39pm

physics
A fight aircraft needs to emergency land due to engine breakdown. The pilot can control the approach velocity to 250 km/hr when the aircraft tires touch the ground. The best deceleration of its braking system is 10 m/s2 . How long will the runway is required for a safe landing?
Monday, August 11, 2014 at 3:52pm

physics
the 900 kg car was traveling south and collided with the 2000kg car traveling west. they both got tangled and moved away from the impact point as one mass at 16.0m/s in the direction 24degrees west of south. what was the initial speed of each prior to the collision?
Monday, August 11, 2014 at 1:03pm

physics
calculate the number of molecules in 30g water
Monday, August 11, 2014 at 10:30am

Physics
a ball dropped from rest bag by a little boy from window of a three storey apartment how far has it fallen fter 3s What is the ball's velocity after 4 second of fall How far does ball fall during the lst 4 second?
Monday, August 11, 2014 at 7:03am

PHYSICS
dETERMINE the horizontal force needed to accelerate a 50 kg grocery cart from rest to 0.90 m/s in 2.8s if the coefficient of friction between the cart and the floor is 0.20?
Monday, August 11, 2014 at 6:05am

pHYSICS`
dETERMINE THE HORIZONTAL FORCE needed to accelerate a 50kg grocery cart from rest to 0.90 m/s in 2.8s if the coefficient of friction between the cart and the floor is 0.20 ?
Monday, August 11, 2014 at 6:03am

physics
A HPHS012 student throws a water balloon vertically downward from the top of a building. The balloon leaves the thrower’s hand with a speed of 6.00m/s. Air resistance may be ignored, so the water balloon is in free fall after it leaves the thrower’s hand.
Monday, August 11, 2014 at 2:02am

physics
Two boat landings are 3.0 km apart on the same bank of a stream that flows at 1.6 km/h. A motorboat makes the round trip between the two landings in 50 minutes. What is the speed of the boat relative to the water? How do I factor in the fact that velocity is subtracted by 1.6 ...
Sunday, August 10, 2014 at 11:04pm

physics
Two boat landings are 8.0 km apart on the same bank of a stream that flows at 2.8 km/h. A motorboat makes the round trip between the two landings in 50 minutes. What is the speed of the boat relative to the water?
Sunday, August 10, 2014 at 10:51pm

physics
Two boat landings are 8.0 km apart on the same bank of a stream that flows at 2.8 km/h. A motorboat makes the round trip between the two landings in 50 minutes. What is the speed of the boat relative to the water? I think it is something along the lines of 4/t+2.8 + 4/t-2.8 =5...
Sunday, August 10, 2014 at 10:29pm

physics
an object moving on the x axis with a constant acceleration increases its x coordinate by 108 m in a time of 9.5 s and has a velocity of 20 m/s at the end of this time. Determine the acceleration of the object during this motion?
Sunday, August 10, 2014 at 7:48pm

math
In a high school, 30% of student take physics, 15% of students take chemistry. The rest of students are taking biology. What is minimum student taking biology? A.7 B.8 C.9 D.10 E.11
Sunday, August 10, 2014 at 4:20pm

Physics
While sitting on a tree branch 11m above the ground, you drop a chestnut. When the chestnut has fallen 2.7m , you throw a second chestnut straight down. What initial speed must you give the second chestnut if they are both to reach the ground at the same time? I know I am ...
Sunday, August 10, 2014 at 2:54pm

physics
a car with a mass of 900kg and a car with a mass of 2000kg collide. one car is moved away from the impact point as one mass at 16.0m/s in the direction 24 degrees west of south. what was the initial speed of each car prior to the collision?
Sunday, August 10, 2014 at 1:01pm

physics
a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.
Sunday, August 10, 2014 at 12:57pm

physics
Ball A is dropped from the top of a building of height h at the same instant that ball B is thrown vertically upward from the ground. When the balls collide, they are moving in opposite directions, and the speed of A is twice the speed of B. At what height does the collision ...
Sunday, August 10, 2014 at 10:12am

physics
A person walk up a stalled escalator in 90sec.when standing on the same escalator now moving,he is carried in 60 sec.the time he would take to walk up the moving escalator will be.
Sunday, August 10, 2014 at 7:53am

physics
If you heat a thin circular ring in a oven, does the rings hole get larger or smaller.why?
Sunday, August 10, 2014 at 6:22am

physics
A ball hits a wall horizontally at 6.0 m/s. It rebounds horizontally at 4.4 m/s. The ball is in contact with the wall for 0.040 s. What is the acceleration of the ball?
Sunday, August 10, 2014 at 6:17am

physics
a storage battery of emf 8V internal resistance 1 ohm is being charged by a 12 V d.c source using a 15 ohm resistor in series in the circuit. Calculate the current
Sunday, August 10, 2014 at 4:40am

PHYSICS
Two dogs pull horizontally on ropes attached to a post; the angle between the ropes is 62.0∘. Dog A exerts a force of 270N , and dog B exerts a force of 302N . Find the magnitude of the resultant force. Find the angle the resultant force makes with the rope of dog A.
Sunday, August 10, 2014 at 4:31am

PHYSICS
A dockworker applies a constant horizontal force of 71.0N to a block of ice on a smooth horizontal floor. The frictional force is negligible. The block starts from rest and moves a distance 10.0m in a time of 5.50s . If the worker stops pushing after 5.50s , how far does the ...
Sunday, August 10, 2014 at 4:29am

physics
A stone is projected vertically upwards with a velocity 10m/s .Find the maximum height reached by the body (g=10m/sec)
Sunday, August 10, 2014 at 3:29am

physics
A certain howitzer has a barrel 7.6 meters long and fires a 65kg projectile 20cm in diameter at a mzzle speed of 400m/s. Use three different ways, each based on an important physical principle, to find the average force on the projectile while it is in the howitzer barrel. Hmm...
Saturday, August 9, 2014 at 11:14pm

physics
A car whose speed is 90km/hr rounds a curve 180m in radius that is properly banked for a speed of 45km/h. FIind the minimum coefficient of friction between tires and road that wil permit the car to make turn. I alreadly saw the same question in here. But they uses 'tan'...
Saturday, August 9, 2014 at 11:07pm

physics
A superhero is running toward a skyscraper to stop a villain from getting away. As he is moving, he looks up at the top of the building and his line of sight makes a 33.0° angle with the ground. After having moved 300 m, he looks at the top of the building again, and ...
Saturday, August 9, 2014 at 7:00pm

physics
A swimmer heads directly across a river, swimming at 1.5 m/s relative to the water. She arrives at a point 30 m downstream from the point directly across the river, which is 87 m wide. (c) In what direction should the swimmer head so as to arrive at the point directly opposite...
Saturday, August 9, 2014 at 2:45pm

physics
Two boat landings are 8.0 km apart on the same bank of a stream that flows at 2.8 km/h. A motorboat makes the round trip between the two landings in 50 minutes. What is the speed of the boat relative to the water?
Saturday, August 9, 2014 at 2:36pm

physics
Ball A is dropped from the top of a building of height h at the same instant that ball B is thrown vertically upward from the ground. When the balls collide, they are moving in opposite directions, and the speed of A is twice the speed of B. At what height does the collision ...
Saturday, August 9, 2014 at 2:35pm

physics
You have designed a rocket to be used to sample the local atmosphere for pollution. It is fired vertically with a constant upward acceleration of 17 m/s2. After 20 s, the engine shuts off and the rocket continues rising (in freefall) for a while. (Neglect any effects due to ...
Saturday, August 9, 2014 at 2:30pm

physics
You have designed a rocket to be used to sample the local atmosphere for pollution. It is fired vertically with a constant upward acceleration of 17 m/s2. After 20 s, the engine shuts off and the rocket continues rising (in freefall) for a while. (Neglect any effects due to ...
Saturday, August 9, 2014 at 2:18pm

physics
A swimmer heads directly across a river, swimming at 1.5 m/s relative to the water. She arrives at a point 30 m downstream from the point directly across the river, which is 87 m wide.
Saturday, August 9, 2014 at 1:59pm

physics
An object has a weight of 5.10 (N) AT SEA LEVEL. What is the acceleration due to gravity on the object if it is placed in a spaceship?
Saturday, August 9, 2014 at 1:54pm

physics
You are riding in a boat whose speed relative to the water is 7.4 m/s. The boat points at an angle of 24.8° upstream on a river flowing at 15.2 m/s. Find the time it takes for the boat to reach the opposite shore if the river is 26.1 m wide.
Saturday, August 9, 2014 at 1:49pm

physics
a particuler moves along the sides AB,BC,CD of a square of side 25m with a speed of 15m/s. Its average velocity is?
Saturday, August 9, 2014 at 1:36pm

physics
a family goes on vacation for a week and leaves on a fan that consumes electricity at the rate of 200 watts. If the electricity is $0.14/kWh, how much does it cost to run the fan during this time?
Saturday, August 9, 2014 at 10:29am

physics
a 62.0kg bungee jumper jumps from a bridge. she is tied to a bungee cord whose unstretched length is 12.0 m and falls a total of 31m a) calculate the spring constant k of the bungee cord and b) calculate the maximum acceleration she experiences.
Saturday, August 9, 2014 at 10:26am

physics
a particle with velocity of 2m/s at t= 0 moves along a straight line with constant acceleration of 0.2m/s2. find the displacement of the particle in 10 seconds
Saturday, August 9, 2014 at 6:54am

Physics
A man is walking under an inclined mirror at a constant velocity Vms-1.along the X axis. If the mirror is inclined at an angle θ with the horizontal, then what is the velocity of the image?.
Saturday, August 9, 2014 at 3:40am

Physics
A 97 dodge neon locks it's brakes up and skids 15 ft before hitting a motorcyclist then continues to skid another 130 ft without throwing the rider or motorcycle out from in front of the car. The only damage to car is busted head light and bumper comes off the motorcyclist...
Saturday, August 9, 2014 at 12:34am

Physics
A child with a mass of 83 kg is on top of a water slide that is 12 m long and inclined 30 degrees with the horizontal. How fast is the child going at the bottom of the slide (a) if the slide is frictionless? (b) if the coefficient of friction is 0.30?
Friday, August 8, 2014 at 10:32pm

Physics
A train is moving parallel and adjacent to a highway with a constant speed of 28 m/s. Initially a car is 29 m behind the train, traveling in the same direction as the train at 42 m/s and accelerating at 3 m/s^2. What is the speed of the car just as it passes the train?
Friday, August 8, 2014 at 1:13pm

physics
A 1.23-kg copper pot contains 2.17 L of water. Both pot and water are initially at 18.3°C. How much heat must flow into the pot and the water to bring their temperature up to 93.1°C? Assume that the effect of water evaporation during the heating process can be ...
Friday, August 8, 2014 at 1:08pm

Physics
An egg is dropped from 75 cm, what velocity is egg at when it hits the floor. What is the maximum height it can be dropped from to withstand impact velocity of 1.7ms-1 I used V*2 = v*2 + 2ad V = sqrt 0 + 2 x -9.8 x .75 = -3.83m/s 0.14744 m rounded to 0.15 m
Friday, August 8, 2014 at 9:16am

Physics
I just want some help checking my homework... Question: A care travelling at a velocity of 42ms-1 suddenly loses engine power and slows at a constant rate. It comes to rest after 75 seconds. a what is the acceleration during this time ? b how far did the care travel before ...
Friday, August 8, 2014 at 7:25am

Physics
If the coefficients of static and kinetic friction between a 20 kg block that sits on top of a 100 kg block are both essentially the same value of 0.5, determine the acceleration of each block for a force pulling on A of 60 N. Bottom block sits on a friction-less floor. (I was...
Friday, August 8, 2014 at 1:11am

physics 2
- Matter is made of charged particles - The motion of charged particles produces electromagnetic waves - Since light is an electromagnetic wave, the color of a substance is ultimately related to the way that charged particles in that substance can move around. Quantum ...
Thursday, August 7, 2014 at 10:56pm

Physics
A gun is fired parallel to the ground. At the same instant, a bullet of equal size and mass next to the muzzle is released and drops to the ground. Which hits the ground first and why? I think that the bullets will hit the ground at the same time because the bullet that is ...
Thursday, August 7, 2014 at 9:36pm

physics
A particle undergoes two displaments , measured from the positive x-axis, with counterclockwise positive.The first has a magnitude of 11 m and makes an angle of 88 with the positive x-axis. The resultant displacement has a magnitude of 6.8 m direceted at an angle of 115 from ...
Thursday, August 7, 2014 at 3:27pm

physics
A block of mass m takes time t to slide down on a smooth inclined plane of angle of inclination theta and height h. If same block slids down on a rough inclined plane of same angle of inclination and some height and takes time n times of initial value then coefficient of ...
Thursday, August 7, 2014 at 1:56pm

physics 2
- Matter is made of charged particles - The motion of charged particles produces electromagnetic waves - Since light is an electromagnetic wave, the color of a substance is ultimately related to the way that charged particles in that substance can move around. Quantum ...
Thursday, August 7, 2014 at 1:47pm

Physics
a bus travels from one point to another wuth a speed of 40km/h and returns with a speed of 60km/h.what is e average speed and average velocity of the bus?
Thursday, August 7, 2014 at 11:48am

physics
Show that the critical velocity of body revolving in cercular orbit very close to the surface of a planet of radiuis R and meandencity.
Thursday, August 7, 2014 at 5:32am

physics
a bus travels from one point to another wuth a speed of 40km/h and returns with a speed of 60km/h.what is e average speed and average velocity of the bus?
Thursday, August 7, 2014 at 2:56am

PHYSICS
3) A 10.0 kg object is hanging by a massless rope in an elevator that is traveling upward. The tension in the rope is measured to be 75.0 N. What are the magnitude and direction of the acceleration of the elevator?
Wednesday, August 6, 2014 at 8:49pm

Physics
2) A child sits on a merry-go-round, 1.5 meters from the center. The merry-go-round is turning at a constant rate, and the child is observed to have a radial acceleration of 2.3m/s^2. How long does it take for the merry-go-round to make one revolution?
Wednesday, August 6, 2014 at 8:24pm

Physics
1) A car moving along a straight stretch of road at 60 mph [26.7 meters/sec]. The driver makes slams on his breaks locking them so that the car skids to a stop. Assume a constant braking force due to friction, and a kinetic friction coefficient of 0.70 between the tires and ...
Wednesday, August 6, 2014 at 7:50pm

Physics
Average velocity
Wednesday, August 6, 2014 at 2:12pm

physics
1. Two carts, one twice the mass of the other, experience the same force for the same time. What is their difference in momentum? What is their difference in kinetic energy?
Wednesday, August 6, 2014 at 1:12pm

PHYSICS
A 15g bullet is fired horizontally into a block of wood with a mass of 2.5 k and embedded in the block. Initially the block of wood hangs vertically and the impact causes the block o swing so that its center of mass rises 15cm. find the velocity of the bullet just before the ...
Wednesday, August 6, 2014 at 1:03pm

physics
calculate the amount of work it takes to increase a cars speed from 10mph to 30 mph and from 50mph to 60mph. Is more work required for 10mph to 30mph?
Wednesday, August 6, 2014 at 12:17pm

physics
a man with a 45kg mass dove 12m from a building into 0.32m of water. a)what was his kinetic energy when he hit the water? b)what average net force was exerted on him when he stopped?
Wednesday, August 6, 2014 at 11:41am

physics
a 1.2 kg ball drops vertically onto the floor, hitting with a speed of 25m/s. it rebounds with an initial speed of 10m/s. a) what impulse acts on the ball during the contact? b) if the ball is in contact with the floor for 0.20 s, what is the magnitude of the average force on ...
Wednesday, August 6, 2014 at 11:38am

PHYSICS
what work must a diesel engine in an 18,000kg truck do to increase its speed from 30.m/s to 40 m/s in 5.0s? what average force did the engine exert? what power was needed (in horsepower)
Wednesday, August 6, 2014 at 10:16am

PHYSICS
a marksman fires a bullet(mB=5.00g) horizontally with a velocity of 300.m/s from a rifle(mR=3.00kg)What is the recoil velocity of the rifle?
Wednesday, August 6, 2014 at 10:07am

PHYSICS
a constant force of 6.00N acts on a 3.00kg object for 10.0s. what are the changes in the objects momentum and velocity?
Wednesday, August 6, 2014 at 10:04am

PHYSICS
when a mass of 2.5kg string is attached to a spring it stretches 42cm. a) find the constant of the spring 'k' b) how much force is required to stretch the spring 50cm? c) how much energy is stored in the spring when stretched 0.35cm?
Wednesday, August 6, 2014 at 10:03am

Physics
What is elastic collision
Wednesday, August 6, 2014 at 7:44am

Physics
We have a projectile launched upward with an initial horizontal velocity of 20 m/s and an initial vertical velocity of 30 m/s. 1. What is the actual initial speed of the projectile? 2. What happens to the horizontal component of the velocity as the projectile flies through the...
Wednesday, August 6, 2014 at 7:35am

Physics
A hunter holds a 3kg rifle and fires a bullet of mass 5g with a muzzle velocity of 300m/s. What is the final kinetic energy of the bullet and the riffle?
Wednesday, August 6, 2014 at 7:22am

physics
a ball of mass 5kg is dropped from a height of 78.4m,the time taken by the ball to reach the ground is?
Wednesday, August 6, 2014 at 3:23am

physics
why is the surface of a bell made large?
Tuesday, August 5, 2014 at 10:21pm

physics
A projectile is launched at an angle of 30 to the horizontal with a speed of 30 m/s. How does the horizontal component of its velocity 1.0 s after launch compare with its horizontal component of velocity 2.0 s after launch?
Tuesday, August 5, 2014 at 8:58pm

physics
the mass of the water is 131 kg and its initial temperature is 24.2°C, how much energy must the water transfer to its surroundings in order to freeze completely? The specific heat of water is 4186 J/kg·K, and the latent heat of fusion is 333 kJ/kg
Tuesday, August 5, 2014 at 7:39pm

physics
As it passes over Grand Bahama Island, the eye of a hurricane is moving in a direction 25.0° north of east with a speed of 40.6 km/h. Three hours later, the course of the hurricane suddenly shifts due north, and its speed slows to 23.0 km/h. How far from Grand Bahama is ...
Tuesday, August 5, 2014 at 5:43pm

Physics
A stone projected vertically upward with a speed of 30ms from the top of a tower of height 50m neglecting the air resistance.determine the maximum height it reach from the ground
Tuesday, August 5, 2014 at 5:34pm

physics
The rate of burning of fuel in a rocket is 50 g/sec and comes out with a velocity 4X1000 sec. then find the force extended by fuel on the rocket.
Tuesday, August 5, 2014 at 10:09am

college physics
Calculate the angular speed of the moon if it makes a revolution around the earth in 27.3 days?
Tuesday, August 5, 2014 at 4:07am

college physics
A wheel starts from rest and increase it's rotational speed;time required to reach that speed;Uniform angular acceleration.
Tuesday, August 5, 2014 at 4:06am

college physics
What is the force applied in the direction of the wire at a point attached to the patient in a traction system, if the mass applied is equal to 5kg?
Tuesday, August 5, 2014 at 4:04am

Physics
Why can you exert a greater force on the pedals of a bike if you pull up on the handlebars? Does it have anything to do with one of Newton's 3 laws? I'm not sure how to approach this question.
Monday, August 4, 2014 at 7:55pm

physics
calculate the amount of heat energy required to melt a 1kg iron ingot initially at 20 ¡ãC? (heat of fusion for Fe is 33.0 J/g
Monday, August 4, 2014 at 7:44pm

physics
A projectile is fired with an initial speed of 65.2 m/s at an angle of 34.5 degree above the horizontal on a long flat firing range. Determine (a) The maximum height reached by the projectile, (b) The total time in the air, (c) The total horizontal distance covered (that is, ...
Monday, August 4, 2014 at 7:37pm

physics
100 grams of a liquid with a temp of 70 degreess celcius and a specific heat of 4 J/K/gram is poured into an aluminum pan having a mass of 4000 grams and an initial temp of 20 degrees. with a specific heat capacity of 0.9. what is the final temp of teh liquid in the pan after ...
Monday, August 4, 2014 at 3:33pm

physics
An astronaut in a spaceship is listening to his music. Calculate the time it takes to play a 4.00 minute song at 0.1c
Monday, August 4, 2014 at 2:25pm

science (physics)
A projectileis given an initial velocity of icap + 2jcap . The catesian equation of its path
Monday, August 4, 2014 at 12:50pm

science (physics)
A projectileis given an initial velocity of icap + 2jcap . The catesian equation of its path
Monday, August 4, 2014 at 11:33am

Physics
The rate of volume flow of water through a canal is found to be a function of cross -section of canal and velocity of water.show that the rate of volume flow is proportional to the velocity of flow of water
Monday, August 4, 2014 at 10:59am

Physics-help please!
A wave on a rope is 6.1m . a.) What is the wavelength of this wave? b.) If the frequency of the wave is 6.2Hz, what is the wave velocity?
Monday, August 4, 2014 at 10:15am

PHYSICS
THE MASS OF VENUS IS 81.5% OF THE EARTH AND ITS RADIUS IS 94.9% THAT OF THE EARTH. A)COMPUTE THE ACCELERATION DUE TO GRAVITY ON THE SURFACE OF VENUS FROM THESE DATA.B)IF A ROCK WEIGHS 75.0N ON EARTH,WHAT WOULD IT WEIGH ON THE SURFACE OF VENUS?
Monday, August 4, 2014 at 9:08am

PHYSICS
AT WHAT DISTANCE ABOVE THE SURFACE OF THE EARTH IS THE ACCELERATION DUE TO EARTH'S GRAVITY 0.980M/S² IF THE ACCELERATION DUE TO GRAVITY AT THE SURFACE HAS MAGNITUDE 9.80M/S²
Monday, August 4, 2014 at 8:46am

physics-please help
A proton, traveling with a velocity of 6.8 × 106 m/s due east, experiences a magnetic force that has a maximum magnitude of 8.6 × 10-14 N and direction of due south. What are the magnitude and direction of the magnetic field causing the force? If the field is up, ...
Monday, August 4, 2014 at 7:18am

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