Thursday

August 28, 2014

August 28, 2014

Number of results: 22,959

**Phys**

Three blocks on a frictionless horizontal surface are in contact with each other. A force F is applied to block A (mass mA). (a) Draw a free body diagram for each block. I've drawn it and it looks like this, but I'm not sure if I'm including everything. ^normal force F-->|...
*February 7, 2013 by anonymous*

**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 ...
*March 28, 2011 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 ...
*March 27, 2011 by Mallory*

**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 ...
*May 3, 2011 by HELP!!!!*

**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 ...
*May 5, 2011 by Hard to solve ..please help!!!!*

**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 ...
*January 24, 2012 by Anonymous*

**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 ...
*April 13, 2013 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 ...
*April 13, 2013 by monica*

**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 ...
*December 5, 2007 by katlin*

**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 (...
*February 13, 2014 by Joe*

**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 ...
*February 21, 2014 by Suaad*

**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.
*October 21, 2012 by Anonymous*

**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 ...
*November 2, 2013 by Jason*

**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...
*April 24, 2011 by aly*

**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 (J) 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 ...
*July 24, 2013 by Eric*

**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?
*November 6, 2011 by Danielle*

**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 ...
*January 4, 2012 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 ...
*January 4, 2012 by DB*

**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 ...
*October 13, 2009 by tony*

**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.
*March 8, 2012 by James*

**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?
*October 10, 2011 by Mah*

**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?
*October 7, 2012 by jane*

**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...
*May 10, 2012 by Alica*

**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
*July 10, 2013 by sal*

**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 ...
*December 14, 2007 by Einstein*

**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?)
*November 14, 2012 by rfvv*

**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...
*November 25, 2012 by Alexandra*

**math-average**

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

**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?
*March 30, 2010 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?
*March 30, 2010 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?
*April 4, 2010 by anna*

**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?
*February 7, 2013 by Lisa*

**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 ...
*February 7, 2011 by shay*

**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 ...
*April 12, 2007 by david*

**physics**

I have a question based off of the response to the question I posted below. Sorry, i wanted to make sure that i clearly understood,so My question about the third solution is: Is the horizontal force zero N? or is it 721.3N? A dragster and driver together have mass 918.8 kg. ...
*July 3, 2011 by alexa*

**physics**

A 67.7 kg person jumps from rest off a 3.11 m-high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 1.04 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This ...
*February 19, 2012 by Harry*

**physics**

A 67.7 kg person jumps from rest off a 3.11 m-high tower straight down into the water. Neglect air resistance during the descent. She comes to rest 1.04 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This ...
*February 20, 2012 by Joe*

**physics 11**

A 1200 kg car on a horizontal surface starts from rest and accelerates uniformly to 72 km/h in 20.0 s. Friction exets an average force of 450 N on the car during this time. a) what is the net work done on the car b) how far does the car move during this acceleration c) what is...
*September 27, 2011 by janeae*

**grade 11 physics**

sue drives her 1452 kg car along a straight road at a constant velocity of 30 m/s [E]. Ger brakes suddently give out. she puts the car in neutral and lets it coast for 25 seconds. The air drag decelerates the car to a velocityof 25 m/s [E]. assume a frictionless surface. PART ...
*January 23, 2010 by Laura*

**Physics**

You are the design engineer in charge of the crashworthiness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 51 km/h (32 mph). A new model of mass 1900 kg takes 0.18 s from the time of impact until it is brought to rest. Calculate the...
*November 10, 2010 by Linda*

**Physics**

You are the design engineer in charge of the crashworthiness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 56 km/h (35mph ). A new model of mass 1900 kg takes 0.15 s from the time of impact until it is brought to rest. 1. Calculate ...
*February 14, 2011 by Lisa*

**Physics**

You are the design engineer in charge of the crashworthiness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 56 km/h (35mph ). A new model of mass 1900 kg takes 0.15 s from the time of impact until it is brought to rest. 1. Calculate ...
*February 14, 2011 by kolin*

**Physics**

You are the design engineer in charge of the crashworthiness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 56 km/h (35mph ). A new model of mass 1900 kg takes 0.15 s from the time of impact until it is brought to rest. 1. Calculate ...
*February 15, 2011 by kolin*

**Physics**

A person is making homemade ice cream. She exerts a force of magnitude 23 N on the free end of the crank handle, and this end moves in a circular path of radius 0.35 m. The force is always applied parallel to the motion of the handle. If the handle is turned once every 1.6 s, ...
*February 25, 2008 by Eric*

**physics**

A 62.7-kg person jumps from rest off a 2.98-m-high tower straight down into the water. Neglect air resistance. She comes to rest 1.09 m under the surface of the water. Determine the magnitude of the average force that the water exerts on the diver. This force is ...
*November 28, 2011 by Yuli*

**physics**

A tennis ball has a mass of 0.057 kg. A professional tennis player hits the ball hard enough to give it a speed of 52 m/s (about 117 miles per hour.) The ball moves toward the left, hits a wall and bounces straight back to the right with almost the same speed (52 m/s). As ...
*January 23, 2014 by Sandy*

**Physics**

The driver accelerates a 240.0 kg snowmobile, which results in a force being exerted that speeds up the snowmobile from 6.00 m/s to 28.0 m/s over a time interval of 60.0 s. b. What is the snowmobile's change in momentum? What is the impulse on the snowmobile? c. What is the ...
*January 6, 2010 by Shawn*

**PHYSICS**

A hummingbird is able to hover because, as the wings move downwards, they exert a downward force on the air. Newton's third law tells us that the air exerts an equal and opposite force (upwards) on the wings. The average of this force must be equal to the weight of the bird ...
*October 27, 2010 by Petrik*

**physicss**

What average force is required to stop an 1100 kg car in 9.1 s if it is traveling at 83 km/h?
*November 1, 2010 by Devon*

**science**

What is the average force given to an object by the current of bangladeshi rivers?
*May 12, 2011 by Shuhan mirza*

**science**

What is the average force given to an object by the current of bangladeshi rivers?
*May 12, 2011 by Shuhan mirza*

**Physica**

A box is pulled horizontally by a 60 N force at an average velocity 1.0m/s. The power is
*July 11, 2012 by Q15*

**college physics**

You are the design engineer in charge of the crashworthiness of new automobile models. Cars are tested by smashing them into fixed, massive barriers at 50 km/h (31 mph). A new model of mass 1400 kg takes 0.18 s from the time of impact until it is brought to rest. Calculate the...
*March 14, 2010 by Anonymous*

**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?
*September 21, 2012 by Ellie*

**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...
*October 20, 2011 by Ali*

**science**

a 2 kg mass accelerates at 20 m/s/s while being pushed by a 44 N force. Find the force of friction. Net force = Force pushing - Force friction. The net force here is 2 kg x 20 m/s/s.
*December 30, 2006 by leafprincess*

**PHYSICS**

A 62 kg water skier, moving at 14 m/s , lets go of the towline. Momentum= 868 kgm/s Impulse= -868 Ns 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 during this time? I'm guessing "this time" ...
*January 6, 2012 by Anon*

**physics**

a 1200 kg car goes from 15m/s in 16s. What is the average force acting on it?
*September 19, 2011 by sydni*

**physics**

a 1540 kg truck is traveling at 95 km/hr. what average force is required to stop in 10 seconds
*November 3, 2011 by cody*

**physics**

1000 kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is ? n
*November 11, 2012 by Anonymous*

**Physics**

what is the average force needed to stop a car traveling 28m/s in 55m?
*February 19, 2013 by Tory*

**Physics**

what is the average force needed to stop a car traveling 28m/s in 55m?
*February 19, 2013 by Tory*

**Physics URGENT!!!!**

1.A 75 kg passenger in a van is wearing a seat belt whent he van moving at 15m/s, collides with a conrete wall. The front end of the van collapses 0.50 m as it comes to rest. a) what was the paseenger's kinetic energy before the crash b) What average force did the seat belt ...
*April 9, 2011 by kelly*

**grade 11 physics**

PLEASE HELP - NOBODY ANSWERED MY QUESTION YESTERDAY. sue drives her 1452 kg car along a straight road at a constant velocity of 30 m/s [E]. Ger brakes suddently give out. she puts the car in neutral and lets it coast for 25 seconds. The air drag decelerates the car to a ...
*January 24, 2010 by Laura*

**physics**

A canoe of mass 70 kg with a paddler of mass 55 kg are in a river. If the river's current exerts a force of 15 N [E] while the paddler is paddling with an average force of 22 N [N38degreesW], find the acceleration of the canoe and paddler. Use both a component and ...
*April 7, 2011 by Jess*

**physics**

A canoe of mass 70 kg with a paddler of mass 55 kg are in a river. If the river's current exerts a force of 15 N [E] while the paddler is paddling with an average force of 22 N [N38degreesW], find the acceleration of the canoe and paddler. Use both a component and ...
*April 6, 2011 by Jess*

**physics**

Raul pushes a stalled car with a force of 204 N. If the required force decreases at a constant rate from 204 N to 44.0 N for a distance of 16.3 m in 16.0 s, calculate the average power required to move the car. 204-44=160 160*16.3/16 2608/16 answer: 163 W
*April 3, 2008 by Jon*

**science**

What universal force is primarily responsible for keeping satellite in orbit around earth? Answers are electromagnetic force, strong nuclear force, gravitational force, weak nuclear force. Thank you
*March 3, 2014 by snow*

**TO BOBPURSLEY**

def of average velocity = t^-1 (x - x0) (average velocity = t^-1(x-x0))t=(avearge velocity)t + x0= x - x0 + x0 = x = (average velocity)t + x0 x = (average velocity)t + x0 def of average velocity were costant acceleration is assumed = 2^-1(v0 + v) plug into x = (average ...
*June 18, 2009 by TO ]BOBPURSLEY*

**Physics**

def of average velocity = t^-1 (x - x0) (average velocity = t^-1(x-x0))t=(avearge velocity)t + x0= x - x0 + x0 = x = (average velocity)t + x0 x = (average velocity)t + x0 def of average velocity were costant acceleration is assumed = 2^-1(v0 + v) plug into x = (average ...
*June 19, 2009 by Physics*

**Please help with Physics Quickly**

1. How are impulse and momentum related? (Points : 1) Impulse is the change in momentum of an object. Momentum is the change in impulse acting on an object. Impulse and momentum are always equal in magnitude. Impulse and momentum are the same thing. Question 2. 2. Which of ...
*January 27, 2014 by Anna*

**physics repost**

Raul pushes a stalled car with a force of 204 N. If the required force decreases at a constant rate from 204 N to 44.0 N for a distance of 16.3 m in 16.0 s, calculate the average power required to move the car. 204-44=160 160*16.3/16 2608/16 answer: 163 W
*April 4, 2008 by Jon*

**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...
*March 2, 2012 by Arun*

**Physics**

A helicopter, starting from rest, accelerates straight up from the roof of a hospital. The lifting force does work in raising the helicopter. An 850-kg helicopter rises from rest to a speed of 6.9 m/s in a time of 3.8 s. During this time it climbs to a height of 9.4 m. What is...
*November 2, 2009 by Nikki*

**statistics**

Employees are evaluated as below average, average, or above average. What level of measurement is this? a. nominal b. ordinal c. interval d. ratio
*June 19, 2011 by Anonymous*

**Science**

A car is driving up a hill with a force of 40N. The wind is blowing downhill with a force of 10N. Gravity is affecting th car with a force of 20N. The force of friction is 9N. What is the net force, including direction, of this situation?
*September 30, 2008 by Kate*

**physics**

A box containing supplies is vertically lowered at constant speed by a rope from a hovering helicopter. Consider the following forces that arise in this situation: force 1: the force of the earth pulling on the box force 2: the tension force acting on the box force 3: the ...
*June 8, 2014 by Sam*

**Physics**

what is the average force needed to stop a car (1000kg) traveling 28m/s in 55m?
*February 19, 2013 by Anonymous *

**Math**

An instructor gives regular 20-point quizzes and 100-point exams in a mathematics course. Average scores for six students, given as ordered pairs (x,y) where x is the average quiz score and y is the average test score, are (18, 87), (10, 55), (19, 96), (16, 79), (13, 76), and...
*March 7, 2011 by Re*

**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?
*September 19, 2009 by Rebecca*

**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?
*June 30, 2011 by Diane*

**scientist**

what is the therms " average atomic mass is a .............. average ,and so is calculated from a" normal " average?
*December 6, 2012 by asiya*

**physics**

Bumpers on cars are not of much use in a collision. To see why, calculate the average force a bumper would have to exert if it brought a 1200 kg car (a so-called "compact" model) to a rest in 15 cm when the car had an initial speed of 2 m/s (about 4.5 mph). Bumpers are built ...
*April 14, 2010 by brad*

**Maths**

In a class of 75 students,15 are above average,45 are average and the rest below average achievers.The probability that an above average achieving student fails is 0.005,then an average achieving student fails is 0.05 and the probability of a below average achieving student ...
*August 17, 2014 by Susan*

**physics**

A 45 kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.0 m/s. Her hands are in contact with the wall for 0.80 s. Ignore friction and wind resistance. Find the magnitude and direction of the average ...
*October 14, 2008 by kb*

**Physics**

21) A 46 kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of – 1.2 m /s. Her hands are in contact with the wall for 0.8 s. Ignore friction and wind resistance • Find the magnitude and direction of the ...
*December 4, 2012 by Bill*

**Physics**

Could someone please review my answers and tell me if I am on the right track? Thank you! A student drove to the university from her home and noted that the odometer reading of her car increased by 12.0 km. The trip took 18.0 min. (a) What was her average speed? (b) If the ...
*August 31, 2012 by Miaow*

**Physics**

What is the magnitude of the average force required to stop an 1500 kg car in 8.0 s if the care is traveling at 95 km/h? Sum of F = ma?
*June 13, 2012 by Mike *

**physics**

A test car with a dummy driver of mass 60 kg was propelled towards a rigid wall. If the speed of the dummy driver just before impact was 40m/s and the time between the collision and the dummy coming to the rest was 0.10 s, calculate: (i) the average retardation of the dummy ...
*October 10, 2011 by Mah*

**Microeconomics**

When average total cost is declining then: a) marginal cost must be less than average cost b) marginal cost must be greater than average cost c) average toal cost must be greater than average fixed cost d) average variable cost must be declining. My answer is d but my friend ...
*January 26, 2012 by Nicci*

**Physic**

How does doubling the mass of one object and tripling the distance between another object change the gravitational force betweem them? FG = G M1 M2 / r2 a. Force changes by 2/3 b. Force changes by 2/9 c. Force increases by 9 d. Force decreases by 3 e. No change in force
*February 2, 2011 by Help*

**11th grade**

A 40-kg skater is standing still in front of a wall. By pushing against the wall she propels herself backward with a velocity of -1.8 m/s. Her hands are in contact with the wall for 0.80 s. Ignore friction and wind resistance. Find the magnitude and direction of the average ...
*November 16, 2010 by fgh*

**physics**

A 257kg motor cycle and rider accelerate from rest and reach a velocity of 20 meters per second west. The motor cycle wheels exert an average force 710N east of the road.Explain how the force directed east causes the motorcycle to accelerate west
*January 28, 2014 by Bongiwe*

**physics**

A 0.9 kg hollow ball with a radius of 0.12 m, filled with air, is released from rest at the bottom of a 2.0 m deep pool of water. How high above the water does the ball shoot upward? Neglect all frictional effects, and neglect the ball's motion when it is only partially ...
*December 10, 2006 by Jen*

**Physics**

A 2.9 kg body is at rest on a frictionless horizontal air track when a horizontal force F acting in the positive direction of an x axis along the track is applied to the body. A stroboscopic graph of the position of the body as it slides to the right is shown in the figure. ...
*July 22, 2010 by Dave*

**Math**

The word problem is: Nancy's quiz average is a 74. Her quiz average is 1/4 of her grade. The test average is 3/4 of the total grade. What test average does she need to get at least an 88? Would you be able to set up an equation, and explain how the answer was acheived? Thanks!!!
*October 1, 2008 by Coralia*

**Probability and statistics**

The probability that the life time of randomly chosen device is below average, average,above average are respectively 0.2,0.5,0.3. The probability that of the 3 randomly chosen devices lifetimes of 2 are above average and 1 below average equals a.0.054,b.0.018,c.0.036,d.0.012
*March 1, 2012 by Arun*

**physics**

gravational force deimos, a satellite of amrs, has an average radius of 6.3 km. If the gravational force between deimos and a 3.0 kg rock at its surface is 2.5x10(-2)N..what is the mass of deimos ? Use the Universal Law of gravitation: Force= G Mm/distance^2 Solve for M. i did...
*November 28, 2006 by arielle*

**physics**

When jumping straight down, you can be seriously injured if you land stiff-legged. One way to avoid injury is to bend your knees upon landing to reduce the force of the impact. A 79.1 kg man just before contact with the ground has a speed of 6.27 m/s. In a stiff-legged landing...
*February 23, 2012 by Riley*

**Physics**

A car moving at 8 m/s crashes into a barrier and stops in 0.050 s. There is a 19-kg child in the car. Assume that the child's velocity is changed by the same amount as that of the car, and in the same time period. (a) What is the impulse needed to stop the child in N*s?(b) ...
*November 21, 2010 by Preston*

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