Wednesday

April 16, 2014

April 16, 2014

Number of results: 32,115

**physics**

In a crash test, a truck with mass 2600 kg traveling at 24 m/s smashes head-on into a concrete wall without rebounding. The front end crumples so much that the truck is 0.66 m shorter than before. What is the average speed of the truck during the collision (that is, during the...
*Sunday, November 21, 2010 at 9:38pm by Confused again*

**PHYSICS**

A bat strikes a 0.145kg baseball. Just before impact, the ball is traveling horizontally to the right at 60.0 m/s , and it leaves the bat traveling to the left at an angle of 40degrees above horizontal with a speed of 65.0 m/s . The ball and bat are in contact for 1.75 ...
*Friday, March 30, 2012 at 9:35pm by NOT char*

**Physics**

typically a bullet leaves a standard 45 caliber pistol at 262 m/s. if it takes i millisecond to transverse the barrel, determine the average acceleration experienced by the 16.2 gram bullet within the gun's barrel and then compute the average force exerted on it
*Sunday, November 6, 2011 at 3:59pm by Amanda and Leah*

**physics**

Imagine a car involved in a head-on crash. The driver, whose mass is m, is to be brought uniformly to rest within the passenger compartment by compressing an inflated air bag through a distance sc. Write an expression for the average force exerted on the bag in terms of m, vi...
*Wednesday, May 30, 2012 at 11:33am by johny*

**Physics **

A 0.140 kg baseball traveling 39.0 m/s strikes the catchers mitt, which, in bringing the ball to rest, recoils backward 13cm. Question- What is the average force applied by the ball to the glove? *Sigma Force= mass*acceleration
*Monday, June 11, 2012 at 11:12am by Mr. McKee*

**physics**

A 61.7 kg person jumps from rest off a 2.98 m-high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 1.19 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This ...
*Monday, February 20, 2012 at 2:25pm by nick*

**Physics**

Force x time = momentum change. The momentum change is M [V1-(-V2)] = M (V1+V2) They tell you the time interval that the force acts. Solve for the (average) force.
*Tuesday, May 27, 2008 at 1:07am by drwls*

**Physics**

A 48.8-kg skater is standing at rest in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.88 m/s. Her hands are in contact with the wall for 0.763 s. Ignore friction and wind resistance. Find the average force she exerts on the ...
*Wednesday, January 2, 2013 at 3:19pm by Tim*

**Physics**

a) Set F*X equal to the initial kinetic energy and solve for X. X is the distance and f is the friction force, which is here assumed to equal the propeller force while running at full speed, 780 N b) Divide X by the average speed, V/2.
*Monday, February 25, 2008 at 2:32pm by drwls*

**Physics**

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According to one set of experiments, the average...
*Thursday, November 15, 2007 at 12:32am by Schrei*

**Physics**

A car is traveling at 95km/hr when it collides with a stone wall. The car comes to rest after the first 30 cm of the car is crushed.what was the average horizontal force acting on a 68.1 kg driver while the car came to rest? If 5 cardboard boxes each 1.25 m wide and filled ...
*Sunday, October 2, 2011 at 9:02pm by Dan*

**science**

A 52.0 kg male dancer leaps 0.37 m high. (a) With what momentum does he reach the ground? (c) As the dancer lands, his knees bend, lengthening the stopping time to 0.050 s. Find the average force exerted on the dancer's body. (d) Compare the stopping force with his weight. (...
*Sunday, December 9, 2007 at 5:31pm by marc*

**physics**

I do not think you copied this question carefully. I can not do it without knowing if the 45 degrees is up or down and the magnitude of that velocity. As the second half of the question makes clear, it is impossible to compute "impact force" without knowing the springiness of ...
*Friday, July 27, 2012 at 4:49am by Damon*

**Physics**

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According to one set of experiments, the average...
*Tuesday, November 13, 2007 at 9:06pm by Christina*

**AP physics**

A car is traveling at 60.0 mph when it collides with a stone wall. The car comes to rest after the first foot of the car is crushed. What was the average horizontal force acting on a 150-lb driver while the car came to rest? If five cardboard boxes, each 4 ft wide and filled ...
*Tuesday, September 24, 2013 at 12:26am by leia*

**english**

1. He is of average height. 2. He is around average height. 3. He is a little below average height. 4. He is over average height. 5. He is of much more average height. 6. he is a little average in height. 7. He is more average in height. (Are they all grammatical?)
*Wednesday, November 14, 2012 at 3:52pm by rfvv*

**physics**

Jennifer, who has a mass of 50.0 kg, is riding at 35.0 m/s in her red sports car when she must suddenly slam on the brakes to avoid hitting a deer crossing the road. She strikes the air bag that brings her body to a stop in 0.500 s. What average force does the seat belt exert ...
*Monday, December 3, 2012 at 1:30am by Chelsey Achord*

**physics**

A 72 kg man drops to a concrete patio from a window only 0.60 m above the patio. He neglects to bend his knees on landing, taking 2.0 cm to stop. (a) What is his average acceleration from when his feet first touch the patio to when he stops? m/s2 (b) What is the magnitude of ...
*Thursday, December 11, 2008 at 4:56pm by johnny*

**physics**

A 72 kg man drops to a concrete patio from a window only 0.60 m above the patio. He neglects to bend his knees on landing, taking 2.0 cm to stop. (a) What is his average acceleration from when his feet first touch the patio to when he stops? m/s2 (b) What is the magnitude of ...
*Thursday, December 11, 2008 at 8:04pm by johnny*

**PHYSICS**

average speed during constant acceleration = (end speed+start speed)/2 = (0 + 28.8)/2 = -14.4 m/s Now if you want the average force for the next part of the qustion F = d momentum/ d time = - mass of driver (28.8) /(.93/-14.4)
*Wednesday, February 19, 2014 at 3:18pm by Damon*

**Physics**

The force on an object is described as a function of time equation: F(t) = 3t^2+7t What is the impulse delievered by the force over a period of time from 0 to 5.0s? What is the average force exerted on an object over this time period? If the object has a mass of 2.0kg and is ...
*Tuesday, March 1, 2011 at 12:13pm by melissa*

**Physics**

A set of crash tests consists of running a test car moving at a speed of 12.2 m/s (27.3 mi/hr) into a solid wall. Strapped securely in an advanced seat belt system, a 75.0 kg (165 lbs) dummy is found to move a distance of 0.630 m from the moment the car touches the wall to the...
*Monday, March 18, 2013 at 5:34pm by Haylee*

**Physics**

(Average belt force)x (distnce moved) = initial kinetic energy of dummy = (1/2)*59 kg* (11.8 m/s)^2 = 4108 J Avg. Force = 4108/.66 = 6224 Newtons Acceleration is backwards (negative sign) and equals the speed change divided by time intervsl sqrt (-2aX) = V a = -V^2/(2X) = -105...
*Thursday, February 28, 2008 at 8:17am by drwls*

**physics**

find the average of a block being propelled propelled by an elastic band. very sorry to disturb Mr bobpurlsey again. i am very thankful to you replies. the only problem that lies in the answer is that i haven't been taught hooke's law in Grade 11. which indicates 1/2kx^2 i ...
*Wednesday, June 13, 2007 at 7:49pm by james*

**Physics**

average force
*Tuesday, November 13, 2012 at 11:56pm by tionne*

**math-average**

What is SUM AVERAGE? The professor mentioned that the exam average was 58 [out of 100] and sum average was 144
*Thursday, March 6, 2008 at 3:00pm by see*

**physics**

Presumably the steel ball bounced and changed directions. The momentum change is therefore 0.3 kg*(4.5 + 4.2 kg.s) = 2.61 kg m/s Set that equal to the impulse (Force * time) and divide by the time interval to get the average force.
*Thursday, December 4, 2008 at 11:17pm by drwls*

**physics **

A 57.0 kg diver dives from a height of 15.0 m. She reaches a speed of 14.0 m/s just before entering the water. (a) What was the average force of air resistance (e.g., friction) acting on the diver. (b) What is the force of friction underwater if she reaches a depth of 2.5 m ...
*Saturday, April 13, 2013 at 11:37pm by monica*

**physics **

A 57.0 kg diver dives from a height of 15.0 m. She reaches a speed of 14.0 m/s just before entering the water. (a) What was the average force of air resistance (e.g., friction) acting on the diver. (b) What is the force of friction underwater if she reaches a depth of 2.5 m ...
*Saturday, April 13, 2013 at 11:47pm by monica*

**Physics**

You have just discovered a planetary system consisting of a star (Dagobahr) and its two planets: Rool and Krau. Planet Rool has an average orbital radius 3 times as big as planet Krau. If planet Rool orbits Dagobahr in 2 earth years (1earth year = 365 days). a) how long is the...
*Wednesday, November 14, 2007 at 7:38pm by Andrea*

**physics**

An 879-kg (1943 lb) dragster, starting from rest, attains a speed of 25.6 m/s (57.3 mph) in 0.59 s. (a) Find the average acceleration of the dragster during this time interval. (b) What is the magnitude of the average net force on the dragster during this time?
*Friday, November 26, 2010 at 1:40am by javane*

**Calculating Average Atomicc Mass**

the terms"average atomic mass is............ Average,and so is calculate different from a "normal" Average?
*Saturday, September 8, 2007 at 11:57pm by asiya*

**Physics**

An inexperienced catcher catches a 128 km/h fastball of mass 134 g within 1.01 ms, whereas an experienced catcher slightly retracts his hand during the catch, extending the stopping time to 10.1 ms. What is the average force imparted to the two gloved hands during the catches ...
*Monday, March 28, 2011 at 11:03pm by Mallory*

**Physics**

An inexperienced catcher catches a 128 km/h fastball of mass 134 g within 1.01 ms, whereas an experienced catcher slightly retracts his hand during the catch, extending the stopping time to 10.1 ms. What is the average force imparted to the two gloved hands during the catches ...
*Sunday, March 27, 2011 at 1:43pm by Mallory*

**physics**

b) Since F = m*a The average stopping force can be calculated as: F = 72 kg* -294.25 m/s² = -21.186 kN The negative sign for both the acceleration and stopping force means they are poiting upward, since we took the downward direction to be positive.
*Thursday, December 11, 2008 at 8:04pm by Christiaan*

**physics**

A golf ball of mass 4.50 10-2 kg is struck by a club. Contact lasts 2.35 10-4 s, and the ball leaves the tee with a horizontal velocity of 59.0 m/s. Compute the average force the club exerts on the ball by finding its average acceleration. what is the magnitude?
*Thursday, February 3, 2011 at 11:36am by Anonymous*

**physics**

The physics of a golf ball and kinetic energy. When a 0.045 kg golf ball takes off after being hit, its speed is 41 m/s. a) What is the kinetic energy of the ball after it has been hit? b) How much work is done on the ball by the club? c) Assume that the force of the club acts...
*Sunday, April 24, 2011 at 6:26pm by aly*

**physics**

A hockey goalie is standing on ice. Another player fires a puck (m = 0.22 kg) at the goalie with a velocity of +63 m/s (a) If the goalie catches the puck with his glove in a time of 7.0 10-3 s, what is the average force (magnitude and direction) exerted on the goalie by the ...
*Monday, November 12, 2012 at 6:15am by D*

**Physics**

A hockey goalie is standing on ice. Another player fires a puck (m = 0.22 kg) at the goalie with a velocity of +63 m/s (a) If the goalie catches the puck with his glove in a time of 7.0 10-3 s, what is the average force (magnitude and direction) exerted on the goalie by the ...
*Sunday, November 18, 2012 at 5:49pm by Anonymous*

**Impact force**

A 65.0 kg professional diver performs a dive from a platform 10 m above the water surface. Find the average impact force she experiences in her collision with the water if the collision lasts for 0.800 s.
*Sunday, October 21, 2012 at 9:38pm by Anonymous*

**physics**

A 0.060-kg handball is thrown straight toward a wall with a speed of 9 m/s. It rebounds straight backward at a speed of 6.7 m/s (a) What impulse is exerted on the wall? magnitude 0.942 kg·m/s (b) If the ball is in contact with the wall for 3.0 ms, what average force is exerted...
*Monday, November 7, 2011 at 8:33pm by Amanda*

**Physics**

The Republic of Singapore Air Force uses the AIM-9 Sidewinder air-to-air missile which has a mass of 85.6kg. If the missile can accelerate from 300m/s to 700m/s in 6 seconds, what is the average force exerted on the missile?
*Monday, October 10, 2011 at 11:24am by Mah*

**Physics**

A dragster and driver together have mass 900.7 kg. The dragster, starting from rest, attains a speed of 25.7 m/s in 0.54 s. 1. Find the average acceleration of the dragster during this time interval. Answer in units of m/s^2. 2. What is the size of the average force on the ...
*Friday, February 21, 2014 at 7:59pm by Suaad*

**Physics**

Let F = 3*M*g be the average resistance force in the water. Let d = 5m be the vertical distance the water is penetrated. Let H = the board height above water. Underwater net force * d = Kinetic energy entering water = Initial potential energy (F - M*g)*d = M*g*H 2*M*g*d = M*g*...
*Thursday, February 16, 2012 at 5:12am by drwls*

**Physis**

A bullet of mass of 30g and travelling at a speed of 200msˉ¹ embeds itself in a wooden block. The bullet penetrates a distance of 12cm into the wood. Using the concepts of work done by a force and kinetic energy, determine the average resistive force acting on the bullet.
*Thursday, March 8, 2012 at 4:55pm by James*

**calculus**

is average rate of change and average value the same or will you get a different answer for each this is calculus so it's the mean average. it's using the formula and integrating. I dont understand your question, but I can assure you that average rate of change and average ...
*Thursday, April 12, 2007 at 4:35pm by david*

**physics**

a father pulls hi children in a wagon for 25 minutes covering 1.25 miles on a level sidewalk. he pulls with an average force of 35 lbf at an angle of 45 degrees to the sidewalk. (a) how much work is done (in ft.lbf)? (b) what is the average horsepower required?
*Saturday, May 5, 2012 at 8:48pm by mmk*

**physics**

Find the ratio of the gravitational force on the Moon due to the Earth to the gravitational force on the Moon due to the Sun. (The mass of the Earth is 5.97 1024 kg, the mass of the Moon is 7.36 1022 kg, the mass of the Sun is 1.99 1030 kg, and the average Earth-Moon distance ...
*Thursday, May 5, 2011 at 3:03pm by Hard to solve ..please help!!!!*

**physics**

(1) A helium atom consists of two protons (charge +2e) and two electrons (charge -2e) that are an average of 4.3 x 10^-11 m apart. Find the electrical force between them. Find the gravitational force between them. What is the ratio of gravitational to electrical force? (2) A ...
*Friday, April 17, 2009 at 8:43am by Fred*

**physics**

First convert kg/h to m/s 95 km/h = (95000 m/h)/(3600) s/h = 26.4 m/s Force x Time = momentum change = 1100*26.4 = 2.90*10^4 kg m/s Divide that by the time interval (8.0s) to get the average force in Newtons
*Wednesday, November 21, 2007 at 5:57pm by drwls*

**Physics**

The tops of the towers of the Golden Gate Bridge, in San Francisco, are 227m above the water. Suppose a worker drops a wrench from the top of a tower. If the average force of air resistance is 22% of the force of free fall, with what speed will the wrench hit the water?
*Sunday, November 6, 2011 at 1:56pm by Danielle*

**Physics**

there's three parts, i keep getting these wrong please help. A set of crash tests consists of running a test car moving at a speed of 11.8 m/s (26.4 mi/hr) into a solid wall. Strapped securely in an advanced seat belt system, a 59.0 kg (130 lbs) dummy is found to move a ...
*Thursday, February 28, 2008 at 8:17am by Courtney*

**Science - Physics, I need help with both please. **

A 57.0 kg diver dives from a height of 15.0 m. She reaches a speed of 14.0 m/s just before entering the water. What was the average force of air resistance (e.g., friction) acting on the diver? Bonus: What is the force of friction underwater if she reaches a depth of 2.5 m ...
*Saturday, November 2, 2013 at 11:31pm by Jason*

**winterWx**

A soccer player kicks a soccer ball of mass 0.45 kg that is initially at rest. The force of the kick is given by F(t) = [(5×106)t - (2.5×109)t2] N for 0 ≤ t ≤ 2.0×10-3 s, where t is in seconds. (The player's foot is in contact with the ball for 2.0×10-3 s.) Find ...
*Friday, February 23, 2007 at 2:47am by Physics/Math*

**physics**

Find the ratio of the gravitational force on the Moon due to the Earth to the gravitational force on the Moon due to the Sun. (The mass of the Earth is 5.97 1024 kg, the mass of the Moon is 7.36 1022 kg, the mass of the Sun is 1.99 1030 kg, and the average Earth-Moon distance ...
*Tuesday, May 3, 2011 at 3:20pm by HELP!!!!*

**physics **

Why did you choose 9.8 as the acceleration? It is not falling. its average velocity during stopping is 89/2 km/hr (change that to m/s) So it traveled in that time a distance of avgvelocity*9s... force*distance=initial KE= 1/2 m vi^2 change vi to m/s, then solve for force.
*Thursday, October 1, 2009 at 5:06pm by bobpursley*

**physics**

(Average force)* (Impact duration)= (change in momentum) = 2 M V Avg. Force = 2*(0.2)*26/0.001 Newtons Crunch the numbers. For the second part, solve for the change in momentum. Add it to the initial momentum (which is backwards and negative) to get the final momentum, and ...
*Sunday, August 15, 2010 at 10:51am by drwls*

**physics**

An 855 kg dragster accelerates from rest to 120 km/h in 0.90 seconds. What is the average force exerted on the car? I used the regular f=ma which is f=855*(120-0/.9) which equalled 114000 but that answer is wrong. I don't know another formula am i supposed to add in the ...
*Wednesday, December 5, 2007 at 7:53pm by katlin*

**physics**

A crate is pulled to the right with a force of 84.5 N, to the left with a force of 116.5 N, upward with a force of 685.7 N, and downward with a force of 242 N. What is the net external force in the x direction?
*Sunday, October 7, 2012 at 10:22pm by jane*

**Physics**

Moving at 20 m/s , a remote controlled car of mass 1000kg hits a pile of sand and comes to rest in 10 s. Find the average force that acted to stop the car. The same car now hits a wall and comes to rest in 1s. Find the average force that acted to stop the car. Use knowledge ...
*Thursday, August 24, 2006 at 9:38pm by Abby*

**Projectile physics**

The average speed of a nitrogen molecule in air is about 6.70 ✕ 102 m/s, and its mass is about 4.68 ✕ 10-26 kg. (a) If it takes 3.80 ✕ 10-13 s for a nitrogen molecule to hit a wall and rebound with the same speed but moving in an opposite direction (...
*Thursday, February 13, 2014 at 11:19pm by Joe*

**physics**

find the average of a block being propelled propelled by an elastic band. We know it is uniform acceleration. my attempt on this problem Measure the force applied of elastic band with a newton scale. The more you strecth the farther the distance the block will travel after ...
*Tuesday, June 12, 2007 at 8:11pm by james*

**physics**

i need help with how to find average force
*Sunday, November 21, 2010 at 9:38pm by Mike Hawk*

**physics**

Thanks. the impulse is correct but the magnitude of the average force is not.
*Monday, February 27, 2012 at 1:33pm by Katie*

**Physics**

Dirk pushes on a packing box with a horizontal force of 67.0 N as he slides it along the floor. The average friction force acting on the box is 5.10 N. How much total work is done on the box in moving it 2.20 m along the floor?
*Tuesday, March 30, 2010 at 9:32pm by Max*

**Physics**

Dirk pushes on a packing box with a horizontal force of 67.0 N as he slides it along the floor. The average friction force acting on the box is 5.10 N. How much total work is done on the box in moving it 2.20 m along the floor?
*Tuesday, March 30, 2010 at 11:31pm by Max*

**physics**

Dirk pushes on a packing box with a horizontal force of 67.0 N as he slides it along the floor. The average friction force acting on the box is 3.00 N. How much total work is done on the box in moving it 3.10 m along the floor?
*Sunday, April 4, 2010 at 9:57pm by anna*

**Physics**

I agree, something is missing. The formula is correct if you knew the force, F. In this case, the force is not know, but you can calculate the average force from energy considerations. Work done by friction = F*D = 8.5F using g=9.8 m/s², kinetic energy before hitting the ...
*Thursday, October 22, 2009 at 5:33pm by MathMate*

**Physic**

A 65 kg dancer leaps .32 m high. a) With what momentum does the dancer reach the ground? b) What impulse is needed to make a stop? c) As the dancer lands, the knees bend, lengthening the stopping time to .050 s. Find the average force exerted on the body. d) Compare the ...
*Friday, December 14, 2007 at 1:50pm by Einstein*

**Physics**

In a baseball a pitcher can accelerate a .15kg ball from rest to 98 mi/h in a distance of 1.7m a) what is the average force exerted on a ball during a pitch? b)If the mass of the ball is increased, is the force required of the pitcher increased, decreased or unchanged?
*Thursday, February 7, 2013 at 5:26am by Lisa*

**AP physics**

A 1280-kg car starts from rest and accelerates to 80 km/h in 23.0 s. Friction exerts an average force of 449 N on the car during this time. (a) What is the net work done on the car? J (b) How far does the car move during its acceleration? m (c) What is the net force exerted on...
*Thursday, May 10, 2012 at 8:45pm by Alica*

**Science**

hey im not good with story problems the question is david purley, survived decceration from 173km/h to 0 km/h over a distance of .660 m when his car crashed. Assume that Purley's mass is 70.0kg. What is the mgnitude of the average force acting on him during the crash? Compare ...
*Tuesday, October 13, 2009 at 8:30pm by tony*

**physical science**

Force = rate of change of momentum (in other words m (delta v/ delta t) or m a) F = m (change in velocity/change in time) F = .2 (6/2) = .6 Newtons average during the 2 seconds. Another way, which is really the same, is to say Force * time = impulse which is mass times change ...
*Wednesday, February 6, 2008 at 6:19pm by Damon*

**physics**

Calculate speed when body hits water: (1/2) m v^2 = m g h so v = sqrt(2 g h) average force = change in momentum /time to stop change in momentum = m(v-0) time to stop = distance/average speed = 1.09 / (.5 v)
*Monday, November 28, 2011 at 12:54am by Damon*

**physics**

the frictional force is __ .29 g the time to stop is __ 5.6 / (.29 g) the average velocity is __ (5.6 + 0) / 2 the distance traveled is the average velocity divided by the time
*Wednesday, September 26, 2012 at 6:57pm by Scott*

**physics**

The tops of the towers of the golden gate bridge in san Francisco, are 227m above the water. suppose a worker drops a 655g wrench from the top of a tower. if the average force of air resistance is 2.20 percent of the force of free fall what will the kinetic energy of the ...
*Monday, February 7, 2011 at 12:15pm by shay*

**physics**

on the fourth: comentum is conserved, final momentum is = initial momentum. on the last: vf^2=vi^2+force*distance where distance is average velocity*time or (vf+vi)/2 * t solve for force first two correct.
*Monday, October 15, 2007 at 9:32pm by bobpursley*

**Physics**

impulse = Force x (time of contact) = Final momentum of golf ball = 0.045 kg * 28.0 m/s. \ = change in momentum You don't need the time of contact to do part a. You would need it to compute the average force.
*Tuesday, April 13, 2010 at 8:37am by drwls*

**Math**

(Yes I did, but I'm back. Hey, it's Saturday!) Yes! Not that the _current_ average is .2857, just that the average of the new games that are added on is .2857. If Harry batted exactly .308 in the next 28, his average would stay the same, at .308. If he bats lower, the average ...
*Saturday, October 17, 2009 at 10:09am by jim*

**Physics**

If the puck strikes the goalie's pads and stops in a distance of 4.14 cm, what average force is exerted on the pads? Answer in units of N. This is part three of three parts. 1st Part: A player strikes a hockey puck giving it a velocity of 39.486 m/s. The puck slides across the...
*Sunday, November 25, 2012 at 4:02pm by Alexandra*

**physics**

A 62 kg water skier, moving at 14 m/s , lets go of the towline. a.Find her momentum. 868kgm/s b.What impulse is needed to bring her to rest? -868Ns c.If the water exerts an average force of -275 N on the skier, how long must the force act? 3.16 s d.How far does she travel ...
*Wednesday, January 4, 2012 at 11:17am by JW*

**Physics**

A 62 kg water skier, moving at 14 m/s , lets go of the towline. a.Find her momentum. 868kgm/s b.What impulse is needed to bring her to rest? -868Ns c.If the water exerts an average force of -275 N on the skier, how long must the force act? 3.16 s d.How far does she travel ...
*Wednesday, January 4, 2012 at 2:46pm by DB*

**physics**

A 53.0-kg person jumps from rest off a 12.0-m-high tower straight down into the water. Neglect air resistance. She comes to rest 3.00 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This force is nonconservative
*Wednesday, July 10, 2013 at 3:29pm by sal*

**physics**

A hand-driven tire pump has a 2.50 cm diameter piston and a maximum stroke of 31.0 cm. (a) How much work do you do in one stroke if the average gauge pressure is 2.40 multiplied by 105 N/m2 (about 35 psi)? (You may consider this an isothermal process.) (b) What average force ...
*Wednesday, July 24, 2013 at 6:07pm by Alice*

**physics**

a rock weighing 20.0N falls from a height of 16.0m and sinks 0.600 m into the ground. from energy considerations, find the average force between the rock and the ground as the rock sinks. (avg. force) x (distance sunk) is the3 work done by the soil in decelerating the rock ...
*Wednesday, September 13, 2006 at 8:34am by Maggie*

**Chemistry**

Suppose you are computing an average for a number of type of masses. They might be isotopes in this case. A weighted average would take into account how much of each isotope is there. A "plain" average would just be an average mass for the various n types. (i.e., add them up ...
*Sunday, September 30, 2007 at 10:20am by drwls*

**Physics**

An airplane wing with an average cross sectional area of 10 m^2 experiences a lift force of 5000 N. What is the difference in air pressure, on the average, between the bottom and top of the wing? a. 5000 Pa b. 500 Pa c. 50 Pa d. 50000 Pa e. 10 Pa
*Friday, January 18, 2013 at 1:28am by Will Burns*

**Physics**

An airplane wing with an average cross sectional area of 10 m^2 experiences a lift force of 5000 N. What is the difference in air pressure, on the average, between the bottom and top of the wing? a. 5000 Pa b. 500 Pa c. 50 Pa d. 50000 Pa e. 10 Pa
*Friday, January 18, 2013 at 11:07am by Will Burns*

**Physics**

During a car crash a 65kg person's head goes from traveling at 50km h-1 to stationary in 0.15s. (a)What is the magnitude of the average net force acting on the head of a person with a 4.5kg head? (b)How does this compare with the weight force acting on the person?
*Friday, September 21, 2012 at 8:43pm by Ellie*

**physics**

A 42.0 kg girl jumps on a trampoline. After stretching to its bottom limit, the trampoline exerts an average upward force on the girl over a displacement of 0.50 m. During the time that the trampoline is pushing her up, she experiences an average acceleration of 65 m/s^2. Her ...
*Tuesday, January 24, 2012 at 2:44pm by Anonymous*

**Physics**

The magnitude of the momentum change is 0.1 kg * 50 m/s = 5 kg m/s. (Think about the 3:4:5 velocity vector right triangle) Divide the momentum magnitude change by the time interval to get the average force (or the actual force, if it is assumed constant). F = 5/0.025 = 200 N
*Saturday, January 14, 2012 at 1:30pm by drwls*

**physics**

as a baseball player strikes the ball with his batt the 1kg bat applies an average force of 250N on the .15kg baseball for .2 seconds. A) what is the force applied by the baseball on the bat? what is the acceleration of the baseball? C) what is the speed of the baseball at the...
*Thursday, October 20, 2011 at 9:59pm by Ali*

**Math**

What is the average of seven numbers if the average of the first two is 9 and the average of the last five is 15?
*Saturday, September 19, 2009 at 7:56pm by Rebecca*

**Math - average grade**

I have a 82 average and got a 95 on a test what is my average now?
*Wednesday, February 17, 2010 at 10:32am by Swagger Muffin*

**Probability and statistics**

5. The probabilities that the lifetime of a randomly chosen device is below average, average, above average are respectively 0.2, 0.5, and 0.3. The probability that the 3 randomly chosen devices lifetimes of 2 are above average and 1 below average equals Choose one answer a. 0...
*Friday, March 2, 2012 at 3:23am by Arun*

**Physics**

The average rate of acceleration for a breaking car was -12.2m/s2. If the car had a mass of 925 kg, find the frictional force and direction. a = -12.2m/s2 m = 925 kg Fn = 9074.25 N This is what I've figured out. I don't know how to find the coefficient of friction. If I get ...
*Friday, April 17, 2009 at 12:03am by Lena*

**math**

The average of x and y is 5 and the average of x,y, and z is 8. What is the value of z? a. 19 b. 14 c. 13 D. 11 e. 3 I know that the average of 7 and 3 is 5 (if 7 and 3 are x and y) but I don't know what z is.
*Tuesday, October 14, 2008 at 8:52pm by Mariah*

**scientist**

what is the therms " average atomic mass is a .............. average ,and so is calculated from a" normal " average?
*Thursday, December 6, 2012 at 5:24pm by asiya*

**Chemistry**

If tests are worth 90% & quizzes 10%. What is my average is my test average is a 83 & my quiz average is a 92?
*Thursday, June 30, 2011 at 11:41am by Diane*

**Math**

Forget his current average for a minute. Now, what batting average does 8 hits in 28 make? (Divide 8 by 28.) We don't know how that .308 was made up, but we know that if 8/28 is greater than .308, he's batting better than his past average, so the average will go up. Equally, ...
*Saturday, October 17, 2009 at 10:09am by jim*

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