Wednesday

November 25, 2015
Total # Posts: 366

**Physics**

A 9.67-m ladder with a mass of 25.0 kg lies flat on the ground. A painter grabs the top end of the ladder and pulls straight upward with a force of 242 N. At the instant the top of the ladder leaves the ground, the ladder experiences an angular acceleration of 1.94 rad/s2 ...
*April 18, 2012*

**physics**

Jahna and Raul move onto the setup for experiment 2. They have been asked to determine both the mass of the rod and the mass of the hanging object. They know the length of the rod, the position of the hanging mass, anf the positions and readings of the scales. Determine the ...
*April 16, 2012*

**physics**

Thank You!
*April 16, 2012*

**physics**

Two students, Jahna, and Raul, re performing Experiment 1. To simplify their calculations, each will apply their force perpendicular to the arm of the apparatus. Jahna attaches her spring scale 15cm from the pivot and pulls with a force of 2.5N. Raul attaches his springs scale...
*April 16, 2012*

**Physics**

A grindstone of radius 4.0m is initially spinning with an angular speed of 8.0 rad/s. The angular speed is then increased to 12 rad/s over 4.0s. Assume that the angular acceleration is constant. What is the average angular speed of grindstone?
*April 2, 2012*

**Physics**

The earth has a radius of 6.38 106 m and turns on its axis once every 23.9 h. A. What is the tangential speed (in m/s) of a person living in Ecuador, a country that lies on the equator? (b) At what latitude (i.e., the angle θ in the drawing) is the tangential speed two-...
*March 30, 2012*

**physics**

Some bacteria are propelled by biological motors that spin hair-like flagella. A typical bacterial motor turning at a constant angular velocity has a radius of 1.70e-8 m, and a tangential speed at the rim of 2.32 e-5 m/s. a) What is the angular speed (the magnitude of the ...
*March 30, 2012*

**Physics**

A wind turbine is initially spinning at a constant angular speed. As the wind's strength gradually increases, the turbine experiences a constant angular acceleration of 0.180 rad/s2. After making 2874 revolutions, its angular speed is 139 rad/s. A. What is the initial ...
*March 30, 2012*

**physics**

hi there thanks for trying to help, although my tutor has given the answer as 0.233m. So l am therefor still puzzled by this question ... please help!!!
*March 28, 2012*

**physics**

A block with a mass of 0.5kg is pushed against a horizontal spring of negligible mass and spring constant 450 N/m until the spring is compressed a distance x. When it is released, the block travels along a frictionless, horizontal surface to the bottom of a verticle circular ...
*March 28, 2012*

**physics**

A 1000kg car accelerates from rest to 30m/s over a distance of 20m. a) ignoring friction and air resistance, what is the power generated by the motor? b) if the friction and air resistance is 200N, what is the power generated by the motor?
*March 28, 2012*

**Physics**

ans = 17.85kgm/s^2
*March 17, 2012*

**physics**

The (nonconservative) force propelling a 1.50 103-kg car up a mountain road does 5.10 106 J of work on the car. The car starts from rest at sea level and has a speed of 31.5 m/s at an altitude of 1.90 102 m above sea level. Obtain the work done on the car by the combined ...
*March 14, 2012*

**Physics**

A pitcher throws a 0.140-kg baseball, and it approaches the bat at a speed of 45.0 m/s. The bat does Wnc = 65.0 J of work on the ball in hitting it. Ignoring air resistance, determine the speed of the ball after the ball leaves the bat and is 25.0 m above the point of impact.
*March 14, 2012*

**Physics**

Two stars in a binary system orbit around their center of mass. The centers of the two stars are 7.40 1011 m apart. The larger of the two stars has a mass of 3.40 1030 kg, and its center is 2.50 1011 m from the system's center of mass. What is the mass of the smaller star?
*March 13, 2012*

**Physics**

Two ice skaters have masses m1 and m2 and are initially stationary. Their skates are identical. They push against one another, as shown below, and move in opposite directions with different speeds. While they are pushing against each other, any kinetic frictional forces acting...
*March 13, 2012*

**physics**

By accident, a large plate is dropped and breaks into three pieces. The pieces fly apart parallel to the floor, with v1 = 3.15 m/s and v2 = 1.50 m/s. As the plate falls, its momentum has only a vertical component, and no component parallel to the floor. After the collision, ...
*March 13, 2012*

**physics**

A 1100-kg car is being driven up a 4.0° hill. The frictional force is directed opposite to the motion of the car and has a magnitude of f = 518 N. A force is applied to the car by the road and propels the car forward. In addition to these two forces, two other forces act ...
*March 13, 2012*

**physics**

A 1100-kg car is being driven up a 4.0° hill. The frictional force is directed opposite to the motion of the car and has a magnitude of f = 518 N. A force is applied to the car by the road and propels the car forward. In addition to these two forces, two other forces act ...
*March 13, 2012*

**Physics**

A car accelerates uniformly from rest to 21.0 m/s in 6.1 s along a level stretch of road. Ignoring friction, determine the average power required to accelerate the car if the weight of the car is the following. A) 8.0e3N B) 1.2e4N
*March 13, 2012*

**physics**

When I did this I got the answer 12.91 prior to you responding to me and when I tried the way you said I recieved the same answer but our software is telling me that its wrong and i tried twice.
*March 12, 2012*

**physics**

A baseball (m = 151 g) approaches a bat horizontally at a speed of 39.8 m/s (89 mi/h) and is hit straight back at a speed of 45.7 m/s (102 mi/h). If the ball is in contact with the bat for a time of 1.05 ms, what is the average force exerted on the ball by the bat? Neglect the...
*March 12, 2012*

**Physics**

A car accelerates uniformly from rest to 21.0 m/s in 6.1 s along a level stretch of road. Ignoring friction, determine the average power required to accelerate the car if the weight of the car is the following. A) 8.0e3N B) 1.2e4N (The answer needs to be in Watts)
*March 12, 2012*

**Physics**

A 1100-kg car is being driven up a 4.0° hill. The frictional force is directed opposite to the motion of the car and has a magnitude of f = 518 N. A force is applied to the car by the road and propels the car forward. In addition to these two forces, two other forces act ...
*March 12, 2012*

**physics**

A car (mass=1100kg) is traveling at 32m/s when it collides head on with a sport utility vehicle (mass=2500kg) traveling in the opposite direction. In the collision, the two vehicles come to a halt. at what speed was the sport utility vehicle traveling.
*March 12, 2012*

**physics**

A car (mass=1100kg) is traveling at 32m/s when it collides head on with a sport utility vehicle (mass=2500kg) traveling in the opposite direction. In the collision, the two vehicles come to a halt. at what speed was the sport utility vehicle traveling.
*March 12, 2012*

**physics**

A two staged rocket moves in space at a constant velocity of 4900m/s. The two stages are then separated by a small explosive charge between them. Immediately after the explosion the velocity of the 1200kg upper stage is 5700m/s in the same direction as before the explosion. ...
*March 12, 2012*

**physics**

In a football game, a receiver is standing still, having just caught a pass. Before he can move, a tackler, running at a velocity of 4.5m/s, grabs him. The tackler holds onto the receiver, and and the two move off together with a velocity of 2.6m/s. The mass of the tackler is ...
*March 12, 2012*

**physics**

Am 85kg jogger is heading due east at a speed of 2.0m/s. A 55kg jogger is heading 32 degrees north of east at a speed of 3.0m/s. Find the magnitude and direction of the sum of the momenta of the two joggers.
*March 12, 2012*

**physics**

A space probe is traveling in outer space with a momentum that has a magnitude of 7.5e7 Kg*m/s. A retrorocket is fired to slow down the probe. It applies a force to the probe that has a magnitude of 2.0e6N and a direction opposite to the probe's motion. It fires for a ...
*March 12, 2012*

**Physics**

A space probe is traveling in outer space with a momentum that has a magnitude of 7.5e7 Kg*m/s. A retrorocket is fired to slow down the probe. It applies a force to the probe that has a magnitude of 2.0e6N and a direction opposite to the probe's motion. It fires for a ...
*March 11, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 x 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.11 x 105 m/s to a final velocity of 1.67 x 106 m/s while traveling a distance of 0.0654 m. The ...
*March 11, 2012*

**physics**

A 190-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 32.0° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.876, and the log has an acceleration of 0....
*March 11, 2012*

**Physics**

During a storm, a tree limb breaks off and comes to rest across a barbed wire fence at a point that is not in the middle between two fence posts. The limb exerts a downward force of 283 N on the wire. The left section of the wire makes an angle of 11.8° relative to the ...
*March 11, 2012*

**physics**

Thank you
*March 11, 2012*

**physics**

Traveling at a speed of 18.5 m/s, the driver of an automobile suddenly locks the wheels by slamming on the brakes. The coefficient of kinetic friction between the tires and the road is 0.690. What is the speed of the automobile after 1.41 s have elapsed? Ignore the effects of ...
*March 11, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 x10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.11 x 105 m/s to a final velocity of 1.67 x 106 m/s while traveling a distance of 0.0654 m. The ...
*March 10, 2012*

**math**

find to the nearest minute, all positive values in the interval 0° ≤ θ < 180° that satisfy the equation 2 tan^2 θ - tan θ = 3
*March 7, 2012*

**math**

find to the nearest minute, all positive values in the interval 0° ≤ θ < 180° that satisfy the equation 2 tan^2 θ - tan θ = 3
*March 7, 2012*

**physics**

A small rocket is fired directly upwards with an initial velocity of 100m/s, How many seconds will it take to reach its maximum height?
*February 29, 2012*

**Physics**

Under what conditions would an applied force increase the Kinetic energy of an object?
*February 26, 2012*

**Physics**

A 1.00e2kg crate is being pushed across a horizontal floor by a force of P that makes an angle of 30.0 degrees below the horizontal. The coefficient of Kinetic Friction is 0.200. What should be the magnitude of P, So that the network done by it and the Kinetic Frictional Force...
*February 26, 2012*

**physics**

A steroid is moving along a straight line. A force acts along the displacement of the asteroid and slows it down. The asteroid has a mass of 4.5e4kg and the force causes the speed to change from 7100 to 5500m/s. (A) What is the work done by the force? (B) If the asteroid slows...
*February 26, 2012*

**Physics**

A husband and Wife take turns pulling their child in a wagon along a horizontal sidewalk. Each exerts a constant force and pulls the wagon through the same displacement. They do the same amount of work, but the husband's pulling force is directed 58 degrees above the ...
*February 26, 2012*

**statistics**

A secretary can type 12 names per 60 secods in an average classroom how long will it take her to type all the names
*February 23, 2012*

**physics**

In an automatic clothes dryer, a hollow cylinder moves the clothes on a vertical circle (radius r = 0.31 m), as the drawing shows. The appliance is designed so that the clothes tumble gently as they dry. This means that when a piece of clothing reaches an angle of θ above...
*February 22, 2012*

**Physics**

A satellite moves on a circular earth orbit that has a radius of 6.4 106 m. A model airplane is flying on a 23-m guideline in a horizontal circle. The guideline is parallel to the ground. Find the speed of the plane such that the plane and the satellite have the same ...
*February 22, 2012*

**physics**

A racetrack has the shape of an inverted cone, as the drawing shows. On this surface the cars race in circles that are parallel to the ground, and the surface is at an angle θ = 25°. For a speed of 27 m/s, at what value of the distance d should a driver locate his car...
*February 22, 2012*

**physics**

A "swing" ride at a carnival consists of chairs that are swung in a circle by 12.0 m cables attached to a vertical rotating pole, as the drawing shows. (θ = 61.0°) Suppose the total mass of a chair and its occupant is 196 kg. the tension is 3961.97N Find the...
*February 22, 2012*

**physics**

A centrifuge is a device in which a small container of material is rotated at a high speed on a circular path. Such a device is used in medical laboratories, for instance, to cause the more dense red blood cells to settle through the less dense blood serum and collect at the ...
*February 22, 2012*

**physics**

In the figure below, an object, after being released from its circular path, travels the distance OA in the same time it would have moved from O to P on the circle. The speed of the object on and off the circle remains constant at the same value. Suppose that the radius of the...
*February 21, 2012*

**Physics**

A 260-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 30.0° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.870, and the log has an acceleration of 0....
*February 21, 2012*

**Physics**

A 260-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 30.0° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.870, and the log has an acceleration of 0....
*February 21, 2012*

**physics**

A 260-kg log is pulled up a ramp by means of a rope that is parallel to the surface of the ramp. The ramp is inclined at 30.0° with respect to the horizontal. The coefficient of kinetic friction between the log and the ramp is 0.870, and the log has an acceleration of 0....
*February 21, 2012*

**physics**

The drawing shows box 1 resting on a table, with box 2 resting on top of box 1. A massless rope passes over a massless, frictionless pulley. One end of the rope is connected to box 2, and the other end is connected to box 3. The weights of the three boxes are W1 = 51.0 N, W2...
*February 21, 2012*

**physics**

The drawing shows a wire tooth brace used by orthodontists. The topmost tooth is protruding slightly, and the tension in the wire exerts two forces and ' on this tooth in order to bring it back into alignment. If the forces have the same magnitude of 17.0 N, what is the ...
*February 21, 2012*

**Physics**

The large blade of a helicopter is rotating in a horizontal circle. The length of the blade is 6.7m, measured from its tip to the center of the circle. Find the ratio of the centripetal acceleration at the end of the blade to that which exists at a point located 3.0m from the ...
*February 18, 2012*

**physics**

A net force of 25N is applied for 5.7s to a 12-kg box initially at rest. Waht is the speed of the box at the end of the 5.7s interval?
*February 18, 2012*

**physics**

A 20kg sled is being pulled across a horizontal surface at a constant velocity. The pulling force has a magnitude of 80N and is directed at a angle of 30.0degrees above the horizontal. Determine the coefficient of kinetic friction.
*February 13, 2012*

**Physics**

At an instant when a soccer ball is in contact with the foot of a player kicking it, the horizontal or x component of the ball's acceleration is 810m/s^2 and the vertical or y component of its acceleration is 110m/s^2. The ball's mass is 0.43kg. what is the magnitude ...
*February 12, 2012*

**physics**

When a 58g tennis ball is served, it accelerates from rest to a speed of 45m/s. The impact with the racket gives the ball a constant acceleration over a distance of 44cm. What is the magnitude of the net force acting on the ball?
*February 12, 2012*

**Physics**

A 343-kg boat is sailing 16.2° north of east at a speed of 1.98 m/s. Thirty seconds later, it is sailing 37.5° north of east at a speed of 3.76 m/s. During this time, three forces act on the boat: a 30.3-N force directed 16.2° north of east (due to an auxiliary ...
*February 12, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.21 105 m/s to a final velocity of +2.29 106 m/s while traveling a distance of 0.034 m. The electron'...
*February 12, 2012*

**physics**

Thank You
*February 11, 2012*

**physics**

As a moon follows its orbit around a planet, the maximum gravitational force exerted on the moon by the planet exceeds the minimum gravitational force by 9.8%. Find the ratio rmax/rmin, where rmax is the moon's maximum distance from the center of the planet and rmin is the...
*February 11, 2012*

**physics**

As a moon follows its orbit around a planet, the maximum gravitational force exerted on the moon by the planet exceeds the minimum gravitational force by 9.8%. Find the ratio rmax/rmin, where rmax is the moon's maximum distance from the center of the planet and rmin is the...
*February 9, 2012*

**Physics**

A 343-kg boat is sailing 16.2° north of east at a speed of 1.98 m/s. Thirty seconds later, it is sailing 37.5° north of east at a speed of 3.76 m/s. During this time, three forces act on the boat: a 30.3-N force directed 16.2° north of east (due to an auxiliary ...
*February 9, 2012*

**Physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (see the drawing). Suppose that you lob the ball with an initial speed of 16.0 m/s, at an angle of 47.0°...
*February 9, 2012*

**physics**

An electron is a subatomic particle (m = 9.11 10-31 kg) that is subject to electric forces. An electron moving in the +x direction accelerates from an initial velocity of +5.21 105 m/s to a final velocity of +2.29 106 m/s while traveling a distance of 0.034 m. The electron'...
*February 9, 2012*

**Physics**

An airplane with a speed of 76.8 m/s is climbing upward at an angle of 48° with respect to the horizontal. When the plane's altitude is 560 m, the pilot releases a package. (a) Calculate the distance along the ground, measured from a point directly beneath the point of...
*February 8, 2012*

**physics**

The lob in tennis is an effective tactic when your opponent is near the net. It consists of lofting the ball over his head, forcing him to move quickly away from the net (see the drawing). Suppose that you lob the ball with an initial speed of 16.0 m/s, at an angle of 47.0°...
*February 8, 2012*

**chemistry**

What are the acids in the house?
*January 31, 2012*

**Physics**

Derive an expression for the vertical position of a projectile in terms of its horizontal position. This sometimes called parametric equation or path equation for the projectile. I dont know how to get it please help. Thank you.
*January 30, 2012*

**Physics**

An 18-year-old runner can complete a 10.0-km course with an average speed of 4.39 m/s. A 50-year-old runner can cover the same distance with an average speed of 4.27 m/s. How much later (in seconds) should the younger runner start in order to finish the course at the same time...
*January 29, 2012*

**Physics**

Can you think of any ways to measure instantaneous speed directly?
*January 29, 2012*

**Physics**

What equation gives the velocity as a function of time for an object with constant acceleration?
*January 29, 2012*

**physics**

What equation gives the position as a function of time for an object with constant acceleration?
*January 29, 2012*

**physics**

A dynamite blast at a quarry launches a chunk of rock straight upward, and 2.0s later it is rising at a speed of 15m/s. Assuming air resistance has no effect, calculate its speed A) at launch and B) 5.0s after lauch
*January 29, 2012*

**Physics**

In a historical movie, two knights on horseback start from rest 88.0m apart and ride directly toward each other to do battle. Sir George's acceleration has a magnitude of 0.300m/s (squared), While Sir Alfred's has a magnitude of 0.200m/s (squared). Relative to Sir ...
*January 29, 2012*

**physics**

(a) Just for fun, a person jumps from rest from the top of a cliff overlooking a lake. In falling through a distance H, she acquires a certain speed v. Assuming free-fall conditions, how much farther must she fall in order to acquire speed 2v? Express your answer in terms of H.
*January 20, 2012*

**physics**

Two cars cover the same distance in a straight line. Car A covers the distance at a constant velocity. Car B starts from rest and maintains a constant acceleration. Both cars cover a distance of 487 m in 216 s. Assume that they are moving in the +x direction. Determine (a) the...
*January 20, 2012*

**physis**

The magnitudes of the four displacement vectors shown in the drawing are A = 13.0 m, B = 11.0 m, C = 12.0 m, and D = 27.0 m. Determine the magnitude and directional angle for the resultant that occurs when these vectors are added together.
*January 20, 2012*

**Physics**

A jetliner, traveling northward, is landing with a speed of 67 m/s. Once the jet touches down, it has 765 m of runway in which to reduce its speed to 5.1 m/s. Compute the average acceleration (magnitude and direction) of the plane during landing (take the positive direction to...
*January 20, 2012*

**physics**

An 18-year-old runner can complete a 10.0 km course with an average speed of 4.58 m/s. A 50-year-old runner can cover the same distance with an average speed of 4.36 m/s. How much later (in seconds) should the younger runner start in order to finish the the course at the same ...
*January 20, 2012*

**algebra**

Which is an example of the commutative property? A. –8 + (–13) = –13 + (–8) B. 11 + (–14 + 5) = (11 + (–14)) + 5 C. 16 + (–16) = 0 D. –(22 + 1) = –22 + (–1)
*January 17, 2012*

**football names**

What is the football name of this clue, seven squared?
*January 1, 2012*

**Chem**

using math expressions, define the following: Ka,pKa, pKb, Kb and pKw
*January 1, 2012*

**biostatistics**

A clinical trial is run to assess the effects of different forms of regular exercise on HDL levels in persons between the ages of 18 and 29. Participants in the study are randomly assigned to one of three exercise groups - Weight training, Aerobic exercise or Stretching/Yoga...
*November 26, 2011*

**statistics**

Suppose that in the aerobic exercise group we also measured the number of hours of aerobic exercise per week and the mean is 5.2 hours with a standard deviation of 2.1 hours. The sample correlation is -0.42. a)Is there evidence of a significant correlation between number of ...
*November 26, 2011*

**biostatistics**

7. Consider again the data in problem #6. Suppose that in the aerobic exercise group we also measured the number of hours of aerobic exercise per week and the mean is 5.2 hours with a standard deviation of 2.1 hours. The sample correlation is -0.42. a)Is there evidence of a ...
*November 26, 2011*

**biostatistics**

8. The following data were collected in a clinical trial to compare a new drug to a placebo for its effectiveness in lowering total serum cholesterol. Generate a 95% confidence interval for the difference in mean total cholesterol levels between treatments. New Drug (n=75) ...
*November 26, 2011*

**biostatistics**

Suppose we want to design a new placebo-controlled trial to evaluate an experimental medication to increase lung capacity. The primary outcome is peak expiratory flow rate, a continuous variable measured in liters per minute. the primary outcome will be measured after 6 months...
*November 19, 2011*

**history**

How did african slavery contributed to the economic growth of the british economy
*November 15, 2011*

**Math**

(x-A)(x+A)= x^2 - A^2 hence A^2 =x^2 - 2009 =16 A = square root of 16 = +4, -4
*November 14, 2011*

**Comm II**

When you write a definition of something, I was taught in school that you should not use the word you are defining in the definition. Does this still apply throughout a definition essay? If so, then how?
*November 9, 2011*

**biostatistics**

A studyis run to estimate the mean total cholesterol level in children 2 to 6 years of age. A sample of 9 participants is selected and their total cholesterol levels are measured as follows: 185 225 240 196 175 180 194 147 223 Generate a 95% confidence interval for the true ...
*November 7, 2011*

**biostatistics**

among coffee drinkers, men drink a mean of 3.2 cups per day with a standard deviation of 0.8 cups. Assume the number of coffee drinks per day follows a normal distribution. a. What proportion drinks 2 cups per day or more? b. What proportion drink no more than 4 cups per day? ...
*November 4, 2011*

**CHEMISTRY!! NEED IMMEDIATE HELP PLEASE!!! **

a. Calculate the delta H, delta G, and equilibrium constant for the reaction of methane with Cl2 to give CH3Cl and HCl. Use the following information for your calculations: Bond Dissociation Energies: CH3-H (104.8kcal/mol), Cl-Cl(59.0 kcal/mol), CH3-Cl(85.0 kcal/mol), and H-Cl...
*October 30, 2011*

**business Math**

simple interest 2430 times 0.06 times 1/12
*October 30, 2011*

**algebra**

trains A and B are traveling in the same direction on paraleel tracks. Train A is traveling at 80 miles per hour and train B is traveling at 88 miles per hour. Train a passes a station at 5:10 P.M. If train B passes the same station at 5:40 P.M., at what time will train B ...
*October 23, 2011*