Recent Homework Questions About Physics
The blocks A and B are connected by a piece of spring. Block B rests on a smooth inclined plane of 35° and block A hangs vertically. Calculate the acceleration of the system if the mass of block A is 1.06 kg and that of block B is 6.4 kg
Saturday, February 7, 2015 at 5:36pm
A mass of 0.3 kg is attached to the end of a massless spring of spring constant 0.25 N/m. It is released from rest (t=0). After 0.7 s, the speed of the mass is measured to be 2.0 m/s. What is the amplitude of oscillation?
Saturday, February 7, 2015 at 4:17pm
A particle of charge +18.5C and mass 4.84 × 10-5 kg is released from rest in a region where there is a constant electric field of +578 N/C. What is the displacement of the particle after a time of 1.89 × 10-2 s? 1) F=Eq 2) a=F/m 3) d=vt+1/2at^2 1) F= 10693 N 2) a=...
Saturday, February 7, 2015 at 3:43pm
A 45.0 g ball of copper has a net charge of 2.3 µC. What fraction of the copper's electrons have been removed? (Each copper atom has 29 protons, and copper has an atomic mass of 63.5.)
Saturday, February 7, 2015 at 12:38pm
Two identical pellet guns are fired simultaneously from the edge of a cliff. These guns impart an initial speed of 27.3 m/s to each pellet. Gun A is fired straight upward, with the pellet going up and then falling back down, eventually hitting the ground beneath the cliff. Gun...
Saturday, February 7, 2015 at 9:44am
A soccer player kicks the ball toward a goal that is 23.0 m in front of him. The ball leaves his foot at a speed of 17.6 m/s and an angle of 29.0 ° above the ground. Find the speed of the ball when the goalie catches it in front of the net.
Friday, February 6, 2015 at 11:27pm
A boy standing in a ditch throws a baseball upward toward his father. The ball leaves his hand at ground level, with an initial speed of 16.0 m/s,at an angle of θ = 51°, from the horizontal. The boy's father reaches up and catches the ball over his head, at a ...
Friday, February 6, 2015 at 11:03pm
Determine the banking angle needed to make a high-speed turn off a highway exit ramp with a radius of 720 m if the vehicle is travelling at 80 km/h. Assume there is no friction.
Friday, February 6, 2015 at 7:59pm
A football punter accelerates a 0.59 kg football from rest to a speed of 8.4 m/s in 0.17s. What constant force does the punter exert on the ball? Answer in units of N
Friday, February 6, 2015 at 7:09pm
A bowling ball of mass 3.5 kg moves in a straight line at 4.48 m/s. How fast must a Ping-Pong ball of mass 3.456 g move in a straight line so that the two balls have the same momentum? Answer in units of m/s.
Friday, February 6, 2015 at 7:08pm
A constant force is exerted for a short time interval on a cart that is initially at rest on an air track. This force gives the cart a certain final speed. Suppose we repeat the experiment but, instead of starting from rest, the cart is already moving with constant speed in ...
Friday, February 6, 2015 at 7:06pm
What is the centripetal force acting on an object with a mass of 20 kg moving at a velocity of 10 m/s in a circle with a diameter of 5 m? When the object is moving with circular motion, are the forces balanced on the object? Why or why not?
Friday, February 6, 2015 at 6:34pm
A rope can withstand a maximum tension force of 500N before breaking. If we use the rope to pull a 24 kg bucket of water from a well, what is the maximum acceleration upward we can use without breaking the rope?
Friday, February 6, 2015 at 6:33pm
Human nerve impulses travel at about 10 m/s. Estimate the minimum reaction time from the moment you perceive an obstacle in front of your car and the moment that your foot receives the command to press on the brakes. Consider your height as 1.73m. If the car is traveling at ...
Friday, February 6, 2015 at 6:32pm
Find (a) the magnitude and (b) the direction of the net force on an object given that the following forces act on the object at the same time: 10N east, 20N down, 20N west, 30N down, and 20N up.
Friday, February 6, 2015 at 6:31pm
Assume that there is no friction between m2 and the incline, that m2 = 1.8 kg, m1 = 1.4 kg, the radius of the pulley is 0.10 m, the moment of inertia of the pulley is 3.6 kg m2, and θ = 27.0°. Mass 1 is hanging vertically while mass 2 is on the incline. After mass 2 ...
Friday, February 6, 2015 at 5:41pm
Two 1.30-V batteries-with their positive terminals in the same direction-are inserted in series into the barrel of a flashlight. One battery has an internal resistance of 0.182Ω, the other an internal resistance of 0.139Ω. When the switch is closed, a current of ...
Friday, February 6, 2015 at 5:10pm
A copper cable is to be designed to carry a current of 280A with a power loss of only 2.70W/m. What is the required radius of the copper cable? Answer in units of cm and use 1.7x10-8 Ωm for the resistivity of copper.
Friday, February 6, 2015 at 2:49pm
integrated chemistry and physics
In a water molecule, two hydrogen atoms bind to one oxygen atom. How many lone pairs of electrons will be shown around each hydrogen atom in the Lewis structure of water?
Friday, February 6, 2015 at 12:29pm
A wheel has a rotational velocity of 18·rad/s counterclockwise. You place you hand against the wheel and the friction between your hand and the rim stops it. (a) If it takes 4·s to stop the wheel, what is its rotational acceleration? rad/s2 (b) How far does the ...
Friday, February 6, 2015 at 11:24am
A weight suspended from a spring is seen to bob up and down over a distance of 11 cm twice each second. What is its frequency? Answer in units of Hz. 002 (part 2 of 3) 10.0 points What is its period? Answer in units of s. 003 (part 3 of 3) 10.0 points What is its amplitude? ...
Friday, February 6, 2015 at 10:34am
A stationary observer hears a sound with a frequency of 450 Hz from an approaching car. If the car emits the sound at a frequency of 360 Hz, what would be the speed of the car? (Speed of sound 340 m/s)
Friday, February 6, 2015 at 8:52am
Four identical point charges (+2.51 nC) are placed at the corners of a rectangle, which measures 4.00 m by 7.00 m. If the electric potential is taken to be zero at infinity, what is the potential at the geometric center of this rectangle?
Friday, February 6, 2015 at 1:34am
A stone is dropped into a river from a bridge 43.8 m above the water. Another stone is thrown vertically down 1.65 s after the first is dropped. Both stones strike the water at the same time. What is the initial speed of the second stone?
Friday, February 6, 2015 at 12:52am
The figure gives the acceleration a versus time t for a particle moving along an x axis. The a-axis scale is set by as = 15.0 m/s^2. At t = -2.0 s, the particle's velocity is 7.00 m/s. What is its velocity at t = 6.0 s?
Friday, February 6, 2015 at 12:30am
Determine the ratio of Earth's gravitational force exerted on an 80-kg person when at Earth's surface and when 1000km above Earth's surface. The radius of Earth is 6370 km. I have tried (6370)^2/(7370)^2 = 0.747 and it is wrong??
Thursday, February 5, 2015 at 10:57pm
3 kg object is fastened to a light spring with the intervening cord passing over a pulley. The pulley is frictionless and it's inertia may been neglected. The object is released from rest when the spring is unstretched. If the object drops 10 cm before stopping find the ...
Thursday, February 5, 2015 at 10:51pm
A person walks up a stalled 15 m long escalator in 110 s. When standing on the same escalator, now moving, the person is carried up in 70 s. How much time would it take that person to walk up the moving escalator?
Thursday, February 5, 2015 at 7:56pm
A wildlife researcher is tracking a flock of geese. The geese fly 5.0km due west, then turn toward the north by 35∘ and fly another 3.0km . How far west are they of their initial position? What is the magnitude of their displacement?
Thursday, February 5, 2015 at 6:45pm
A ball thrown horizontally with speed vi = 26.0m/s travels a horizontal distance of d = 60.0m before hitting the ground. From what height h was the ball thrown? Which I got this answer below. h= 26.1 m How do I solve for the one below. If it takes a ball dropped from rest 2....
Thursday, February 5, 2015 at 6:26pm
A ferryboat is traveling north with a speed of 5.50 m/s relative to the water. A passenger is walking with a velocity of 2.50 m/s due east relative to the boat. What is the velocity (magnitude only) of the passenger with respect to the water?
Thursday, February 5, 2015 at 6:24pm
The repulsive electric force between the point charges -6.36 * 10^-6 C and q has a magnitude of 1.32 N when the separation between the charges is 1.07 m. Find the sign and the magnitude of the charge q.
Thursday, February 5, 2015 at 6:17pm
A particle carrying a charge of 6.0uC is located at the origin of a rectangle coordinate system, and a particle carrying a charge of 4.0uC is located at (0,5.0m). What are the magnitude and direction of the electric field at the positions (5.0m,0), (-5.0m,0), and (0,-5.0m)?
Thursday, February 5, 2015 at 5:31pm
A positively charged solid sphere of radius 100 mm has a uniform volume charge density of 250 nC/m^2. Determine the electric field (a) 20 mm, (b) 90 mm, and (c) 110 mm from the center of the sphere.
Thursday, February 5, 2015 at 5:30pm
A speeder passes a parked police car at a constant speed of 20.1 m/s. At that instant, the police car starts from rest with a uniform acceleration of 2.65 m/s How much time passes before the speeder is overtaken by the police car? Answer in units of s
Thursday, February 5, 2015 at 4:44pm
A fire hose ejects a stream of water at an angle of 33.4 ° above the horizontal. The water leaves the nozzle with a speed of 20.1 m/s. Assuming that the water behaves like a projectile, how far from a building should the fire hose be located to hit the highest possible fire?
Thursday, February 5, 2015 at 4:43pm
As you walk to class with a constant speed of 1.65m/s , you are moving in a direction that is 18.8∘ north of east. How much time does it take to change your displacement by 21.0m east?
Thursday, February 5, 2015 at 12:12pm
A wheel on a moving car slows uniformly from 420 rpm to 120 rpm in 4 sec. A. What is the angular acceleration of the wheel? B. What is the angular displacement? How many revolutions? C. How far does the car travel if the radius of the wheel is 0.20cm?
Thursday, February 5, 2015 at 10:23am
A 0.25-kg punk, Initially at rest on a frictionless horizontal surface, is struck by a 0.20kg punk that is initially moving along the x-axis with a velocity of 2.20 m/sec. After the collision, the 0.20 kg punk has a speed of 1.5 m/s at an angle of 37 to the positive x-axis. ...
Thursday, February 5, 2015 at 10:21am
A ball is released from a tower at a height of 100 meters toward the roof of another tower that is 25 meters high. The horizontal distance between the two towers is 20 meters. With what horizontal velocity should the ball be imparted so that it lands on the rooftop of the ...
Thursday, February 5, 2015 at 9:58am
Three point charges are arranged along the x-axis. Charge q 1 = +3.00 ìC is at the origin, and charge q 2 = -5.00 ìC is at x = 0.200 m . Charge q 3 = +8.00 ìC . Where is q 3 located if the net force on q 1 is 7.00 N in the −x direction?
Wednesday, February 4, 2015 at 10:29pm
Jin is sitting on top of a hemispherical, frictionless igloo of radius 2.40 meters. His friend pushes him, giving him an initial speed. Jin slides along the igloo and loses contact with it after he has traveled 1.60 meters along the surface. What was his initial speed?
Wednesday, February 4, 2015 at 9:35pm
A snowmobile is originally at the point with position vector 26.1 m at 95.0° counterclockwise from the x axis, moving with velocity 4.25 m/s at 40.0°. It moves with constant acceleration 1.73 m/s2 at 200°. After 5.00 s have elapsed, find the velocity vector, and ...
Wednesday, February 4, 2015 at 8:53pm
A block and tackle with a velocity ratio of 5 is used to raise a mass of 25kg through a vertical distance of 400M at a steady rate.if the effort is equal to 60N,determine (a)distance moved by the effort (b)work done by lifting the load(c)the loss in energy involved in ...
Wednesday, February 4, 2015 at 5:42pm
A golfer hits a shot to a green that is elevated 3.30 m above the point where the ball is struck. The ball leaves the club at a speed of 17.3 m/s at an angle of 49.0˚ above the horizontal. It rises to its maximum height and then falls down to the green. Ignoring air ...
Wednesday, February 4, 2015 at 4:20pm
Initially, a particle is moving at 5.45 m/s at an angle of 38.5° above the horizontal. Four seconds later, its velocity is 6.24 m/s at an angle of 54.3° below the horizontal. What was the particle's average acceleration during these 4.00 seconds in the x-direction...
Wednesday, February 4, 2015 at 2:50pm
A truck accelerating at 0.0083 meters/second2 covers a distance of 5.8 × 104 meters. If the truck's mass is 7,000 kilograms, what is the work done to reach this distance?
Wednesday, February 4, 2015 at 2:39pm
A ball is shot upwards with an initial speed of 31 m/s. While it is in the air it experiences a constant downwards acceleration of 10 m/s2. Find its velocity 1, 2, 3, and 4 seconds after being released.
Wednesday, February 4, 2015 at 12:41pm
What is the net gravitational field due the sun and earth at the center of the moon? You are given that the mass of the sun in 1.99 x 10^30 and the mass of the earth is 5.97 x 10^24. The distance from the center of the sun to the center of the earth is 1.496 x 10^8 and the ...
Wednesday, February 4, 2015 at 12:13pm
A block of mass 4kg hangs from a spring of force constant 400N/m.the block is pulled down 15cm below the equilibrium position and released. Fimd: a) amplitude, frequency and period of vibration. b) kinetic energy when the block is 10 cm above the equilibrium position. c) time ...
Wednesday, February 4, 2015 at 8:40am
a 2 kg frictionless block is attached to an ideal spring with force constant 300N/m. at t=0 the spring is neither stretched nor compressed and the block is moving in the negative direction at 12m/s. find a) the amplitude and b) the phase angle, c) write a equation for the ...
Wednesday, February 4, 2015 at 7:50am
A .70 m tall barrel is closed on top except for a thin pipe extending 5.3m up from the top. When the barrel is filled with water up to the base of the pipe the water pressure on the bottom of the barrel is 6.9 kPa.
Tuesday, February 3, 2015 at 10:54pm
Three vectors, expressed in Cartesian coordinates. What is the angle of the resultant vector S, T, U measured from the positive x axis? x-comp y-comp S -3.5 +4.5 T 0 -6.5 U +5.5 -2.5 To find the resultant, i'm assuming I have to add the columns up. If that's the case I...
Tuesday, February 3, 2015 at 10:28pm
physics - class 10
An object is kept in front of a concave mirror of focal length 15cm . The image formed is three times to size of object. Calculate two possible distances of the object from the mirror ?
Tuesday, February 3, 2015 at 10:05pm
Physics- Start off good?
Estimate the moment of inertia of a bicycle wheel 67 cm in diameter. The rim of the tire have a combination mass of 1.1kg. (1.1)(67) = 73.3
Tuesday, February 3, 2015 at 10:03pm
physics Electric force
session.masteringphysics. com/problemAsset/1256632/2/RW-20-43.jpg In the figure take q1 = 69μC , q2 = -30μC , and q3 = 16μC. Find the electric force on q3. Fx, Fy = N . How do I solve this problem?
Tuesday, February 3, 2015 at 9:50pm
Physics electric field
A -1.5μC charge experiences a 10i^−N electric force in a certain electric field. What force would a proton experience in the same field? My answer of Fx= 4.17 *10^-13 N is wrong. What am I doing wrong? How do I get the correct answer?
Tuesday, February 3, 2015 at 9:48pm
Physics Coulombs Law
A proton is at the origin and an electron is at the point x = 0.45nm , y = 0.38nm . Find the electric force on the proton. Fx , Fy = N How do I go about solving these 2 problems?
Tuesday, February 3, 2015 at 9:45pm
A charge of 8.0 x 10^(-6) is located inside a sphere. What is the flux through the sphere? Im not sure if this would be just the charge over elipson0. it seems to easy...
Tuesday, February 3, 2015 at 7:02pm
A flat 1.0m^2 surface is vertical at x=2.0m and parallel to the yz-plane. What is the flux through the surface if it is located in a uniform electric field given by E= 26.0i + 42.0j + 62.0k N/C? Explanation if possible :)
Tuesday, February 3, 2015 at 6:35pm
A flat disk 1.0 m in diameter is oriented so that the plane of the disk makes an angle of pi/6 radians with a uniform electric field. if the field strength is 589.0 N/C, find the electric flux through the surface. I know that Flux=(integral)|E|cos(theta)dA but I'm not sure...
Tuesday, February 3, 2015 at 6:17pm
A 98.0 kg ice hockey player hits a 0.150 kg puck, giving the puck a velocity of 49.5 m/s. If both are initially at rest and if the ice is frictionless, how far does the player recoil in the time it takes the puck to reach the goal 13.5 m away?
Tuesday, February 3, 2015 at 5:16pm
A particle leaves the origin with an initial velocity of 4.90 m/s in the x direction, and moves with constant acceleration ax = -2.70 m/s2 and ay = 3.90 m/s2. How far does the particle move in the x direction before turning around? What is the particle's velocity at this ...
Tuesday, February 3, 2015 at 4:26pm
Tarzan is running towards a cliff, ready to swing down rescue Jane from some poisonous snakes, and make it back up to a tree on the other side. For now, we are going to assume energy is conserved and ignore momentum. If the height of the cliff is 10m, the height of the tree on...
Tuesday, February 3, 2015 at 4:23pm
Consider a modified Atwood machine, with a mass sitting on an inclined plane connected by a string which stretches over a pulley connected to a hanging mass. Friction is ignored. Draw a free body diagram for both blocks. Apply Newton's second law to both blocks. If the ...
Tuesday, February 3, 2015 at 4:22pm
Using a coil made of 117 turns of single-strand copper wire, you use a motor to rotate the coil at a constant angular speed of 30.0 revolutions per second at various orientations and locations throughout the room. In one particularly significant orientation, you notice a ...
Tuesday, February 3, 2015 at 11:55am
Astronauts visiting Planet X have a 2.6 -long string whose mass is 5.0g . They tie the string to a support, stretch it horizontally over a pulley 1.8m away, and hang a 1.8kg mass on the free end. Then the astronauts begin to excite standing waves on the string. Their data ...
Tuesday, February 3, 2015 at 11:10am
a metal object is suspended from a spring balance scale. the scale reads 800 N when it is suspended in air and 700 N when the object is completely submerged in water. find the buoyant force, the volume and the density of the metal.
Tuesday, February 3, 2015 at 4:59am
Buffy the Vampire Slayer is buffing up her 0.53 meter long arms by bench pressing. In 31 seconds she can lift 39 kilograms of mass 22 times. How powerful are Buffy's arms?
Tuesday, February 3, 2015 at 2:07am
A 25.0 gram piece of charcoal is found in some ruins of an ancient city. The sample shows a 14C activity, R, of 250 decays/min. How long (in years) has the tree this charcoal came from been dead? I think I have the use the equation: R=lamda*No*e^(-lamda*t) but I am not sure ...
Tuesday, February 3, 2015 at 12:29am
An Earth satellite moves in a circular orbit 946 km above Earth's surface with a period of 103.8 min. What are (a) the speed and (b) the magnitude of the centripetal acceleration of the satellite? I got an answer of 7388.897 m/s for part a, but I'm stuck on part b
Monday, February 2, 2015 at 11:49pm
A small block with mass 0.200 kg is released from rest at the top of a frictionless incline. The block travels a distance 0.440 m down the incline in 2.00 s. The 0.200 kg block is replaced by a 0.400 kg block. If the 0.400 kg block is released from rest at the top of the ...
Monday, February 2, 2015 at 11:40pm
Jack and Jill exercise in a 25.0-m-long swimming pool. Jack swims nine lengths of the pool in 160.1 seconds (2 minutes and 40.1 seconds), while Jill, the faster swimmer, covers ten lengths in the same time interval. Find the average velocity and average speed of each swimmer.
Monday, February 2, 2015 at 11:29pm
A watermelon seed has the following coordinates: x = -8.7 m, y = 1.6 m, and z = 0 m. Find its position vector as (a) a magnitude and (b) an angle relative to the positive direction of the x axis. If the seed is moved to the xyz coordinates ( 3.4 m, 0 m, 0 m), what is its ...
Monday, February 2, 2015 at 10:54pm
Are there even any physics tutors here???
Sorry if I'm sounding as if I'm whining but I'm getting pretty annoyed at how there are many unanswered physics questions. Literally posted a question two months ago and never got any help... This is kinda annoying because the questions get lost in the large feed
Monday, February 2, 2015 at 10:30pm
A small coin, initially at rest, begins falling. If the clock starts when the coin begins to fall, what is the magnitude of the coin\'s displacement between t1 = 0.230 s and t2 = 0.517 s?
Monday, February 2, 2015 at 9:06pm
While standing at the edge of the roof of a building, you throw a stone upward with an initial speed of 7.65 m/s. The stone subsequently falls to the ground, which is 12.7 m below the point where the stone leaves your hand. At what speed does the stone impact the ground? How ...
Monday, February 2, 2015 at 9:05pm
A proton travelling 1.5x10^6 m/s enters 2 vertically charged parallel plates held 0.15m apart. The top plate is held at +250V and the bottom is grounded (0V). A magnetic field can be applied to the area between the plates to counteract the electric force acting on the proton. ...
Monday, February 2, 2015 at 8:53pm
From the window of a building, a ball is tossed from a height y0 above the ground with an initial velocity of 8.50 m/s and angle of 23.0° below the horizontal. It strikes the ground 6.00 s later. If the base of the building is taken to be the origin of the coordinates, ...
Monday, February 2, 2015 at 8:47pm
A thickness planer is a machine that uses a rotating blade to shave a thin layer of wood off the top of the surface. While operating, a piece of wood is inserted such that it causes the machine to struggle and slow down due to resistance of the lumber. Curiously, the 15 amp ...
Monday, February 2, 2015 at 8:43pm