Wednesday

July 23, 2014

July 23, 2014

**Recent Homework Questions About Physics**

Post a New Question | Current Questions

**physics**

In the following figure m_1 = 20.0kg kg and á alpha = 50.9 ∘ ^\circ. The coefficient of kinetic friction between the block and the incline is ì k = 0.40 What must be the mass m 2 of the hanging block if it is to descend 9.00m m in the first 3.00s s after ...
*Thursday, July 4, 2013 at 1:49pm*

**SCIENCE,PHYSICS**

A truck of mass 3000 kg is harnessed to a trailer (Trailer A) of mass 1000 kg. The trailer is hooked to ANOTHER trailer (Trailer B) of mass 500 kg. The truck begins to accelerate to the right at 1 m/s2, pulling the trailers along. What is the ratio of the force the truck ...
*Thursday, July 4, 2013 at 1:59am*

**physics**

A jet starting from rest reaches a speed of 241km/h on 96.0m of runway. Determine the magnitude of the Jet's acceleration? Answer is 23.3m/s^2
*Wednesday, July 3, 2013 at 7:43pm*

**physics**

a train's stopping distance even when full emergency brakes are engaged is 1.3 km. If the train was travelling at an initial velocity of 90km/h(forward), determine its acceleration under full emergency braking
*Wednesday, July 3, 2013 at 7:38pm*

**physics**

If a cyclist traveling at 14.0m/s skids to a stop in 5.60 s, determine the skidding distance assume uniform acceleration? Answer is 39.2m
*Wednesday, July 3, 2013 at 7:37pm*

**physics**

Approaching a flashing pedestrian activated traffic light, a driver must slow down to a speed of 30km/h. If the cross walk is 150m away and the vehicle's initial speed us 59km/h, what must be the magnitude of the car's acceleration to reach the speed limit? Answer is 0...
*Wednesday, July 3, 2013 at 7:32pm*

**Physics**

An aircraft starts from rest and accelerates at 42.5m/s^2 until it takes off at the end of the runway. How long will it take the aircraft to travel down the 2.6km runway? Answer is 11 seconds
*Wednesday, July 3, 2013 at 7:28pm*

**Physics**

How far will a car travel if it starts from rest and experiences an acceleration of magnitude 3.75m/2^2 forward for 5.65 s? Answer is 59.9m
*Wednesday, July 3, 2013 at 7:26pm*

**Physics**

How far will a car travel if it starts from rest and experiences an acceleration of magnitude 3.75m/2^2 forward for 5.65 s? Answer is 59.9m
*Wednesday, July 3, 2013 at 7:25pm*

**Physics**

How far will a humanoid robot travel in 3.0 s, accelerating at 1.0cm/s^2(forward) if its initial velocity is 5.0cm/s(forward) answer is 20cm (forward)
*Wednesday, July 3, 2013 at 7:23pm*

**general physics**

The highest barrier that a projectile can clear is 18.8 m, when the projectile is launched at an angle of 59.0 ° above the horizontal. What is the projectile's launch speed?
*Wednesday, July 3, 2013 at 7:04pm*

**physics**

At a carnival, you can try to ring a bell by striking a target with a 11.6-kg hammer. In response, a 0.413-kg metal piece is sent upward toward the bell, which is 4.22 m above. Suppose that 26.2 percent of the hammer's kinetic energy is used to do the work of sending the ...
*Wednesday, July 3, 2013 at 5:43pm*

**Physics**

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter = 3.000cm = 0.03m Ultimate ...
*Wednesday, July 3, 2013 at 5:13pm*

**Physics**

What is the factor of safety of a steel hanger having an ultimate strength of 630.000MPa and supporting a load of 65000.000N. The steel hanger in question has a cross sectional area of 5.300cm. ANS = (Round to 3 decimal places) Load = 65000.000N Ultimate Strength = 630.000MPa...
*Wednesday, July 3, 2013 at 4:24pm*

**Physics**

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter = 3.000cm = 0.03m Ultimate ...
*Wednesday, July 3, 2013 at 3:57pm*

**Physics**

A steel bar has a rectangular cross section measuring 1.000cm by 2.900cm and is 8.700m in length. A load of 189000.00N causes the bar to extend 1.500mm. Calculate the stress and strain produced. ANS 1 = kPa (3 decimal places) ANS 2 = (6 decimal places) 1.000cm = 0.01m 2.900cm...
*Wednesday, July 3, 2013 at 3:11pm*

**Physics**

A uniform bar 1.000 meters in length and having a cross sectional area of 10.000cm^2 is subjected to a loading of 5750.000 Newtons. This load causes an extension to the bar length of 2.740mm. Calculate the stress and the strain produced. ANS 1 = kPa (Round to 3 decimal places...
*Wednesday, July 3, 2013 at 2:10pm*

**Physics**

HW8_1: CANTILEVERED BEAM WITH TAPERED SQUARE CROSS SECTION A cantilevered beam of length L has a square cross section of side length linearly varying from hA at the free end to hB=3hA, at the fixed support. A concentrated load, P, is applied at the free end A as indicated. ...
*Wednesday, July 3, 2013 at 1:18pm*

**Physics/Mechanics**

HW8_1: CANTILEVERED BEAM WITH TAPERED SQUARE CROSS SECTION A cantilevered beam of length L has a square cross section of side length linearly varying from hA at the free end to hB=3hA, at the fixed support. A concentrated load, P, is applied at the free end A as indicated. ...
*Wednesday, July 3, 2013 at 1:17pm*

**Physics**

1) Calculate the tensile stress in a 33.000mm diameter rod subjected to a pull of 30.000kN. ANS= MPa (Round to 3 decimal places) Diameter = 33.000mm = 0.033m 30.000kN = 30000N Area = pi*d^2/4 = 3.1416 * 0.033^2/ 4 = 3.1416 *0.001089/ 4 = 0.0034212024/ 4 = 8.553006*10^-4 = 0....
*Wednesday, July 3, 2013 at 11:17am*

**Physics**

The ultimate strength of a steel rod is 600.000MPa. if the factor of safety 3.000 is required, what is the maximum permissible load for the rod if it has a diameter of 6.000cm? ANS = kN (Round to 3 decimal place) Ultimate strength = 600.000MPa = 600000000Pa = 600 * 10^6 Factor...
*Wednesday, July 3, 2013 at 11:15am*

**PHYSICS**

How much heat must be added to 1.0 kg of iron to raise its temperature from 20°C to 95°C? (ciron = 0.11 cal/g•°C)
*Wednesday, July 3, 2013 at 12:56am*

**Gen. physics**

A cart is driven by a large propeller or fan, which can accelerate or decelerate the cart. The cart starts out at the position x = 0 m, with an initial velocity of +6.4 m/s and a constant acceleration due to the fan. The direction to the right is positive. The cart reaches a ...
*Tuesday, July 2, 2013 at 9:33pm*

**physics**

A dynamite blast at a quarry launches a rock straight upward, and 2.2 s later it is rising at a rate of 17 m/s. Assuming air resistance has no effect on the rock, calculate its speed (a) at launch and (b)4.4 s after launch.
*Tuesday, July 2, 2013 at 9:31pm*

**gen physics**

(a) What is the magnitude of the average acceleration of a skier who, starting from rest, reaches a speed of 8.02 m/s when going down a slope for 4.28 s? (b) How far does the skier travel in this time?
*Tuesday, July 2, 2013 at 9:29pm*

**gen physics**

A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 3.71 m/s. The car is a distance d away. The bear is 30.0 m behind the tourist and running at 4.49 m/s. The tourist reaches the car safely. What is the maximum possible value for d?
*Tuesday, July 2, 2013 at 9:27pm*

**gen physics**

Vector A has a magnitude of 71 units and points due west, while vector B has the same magnitude and points due south. Find the magnitude and direction of (a) A + B and (b) A - B . Specify the directions relative to due west.
*Tuesday, July 2, 2013 at 9:19pm*

**Physics**

A solid sphere rolls without slipping from rest down a plane at 4.00m long inclined at an angle of 42 degrees with respect to the horizontal as shown in the figure below. Determine the speed at the bottom of the incline.
*Tuesday, July 2, 2013 at 7:49pm*

**Physics**

A street lamp weighs 158 N. It is supported equally by two wires that form an angle of 107˚ with each other. What is the tension of each of these wires?
*Tuesday, July 2, 2013 at 5:55pm*

**Physics**

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter = 3.000cm = 0.03m Ultimate ...
*Tuesday, July 2, 2013 at 4:27pm*

**Physics**

A uniform bar 1.000 meters in length and having a cross sectional area of 10.000cm^2 is subjected to a loading of 5750.000 Newtons. This load causes an extension to the bar length of 2.740mm. Calculate the stress and the strain produced. ANS 1 = kPa (Round to 3 decimal places...
*Tuesday, July 2, 2013 at 4:24pm*

**Physics**

A steel bar has a rectangular cross section measuring 1.000cm by 2.900cm and is 8.700m in length. A load of 189000.00N causes the bar to extend 1.500mm. Calculate the stress and strain produced. ANS 1 = kPa (3 decimal places) ANS 2 = (6 decimal places) 1.000cm = 0.01m 2.900cm...
*Tuesday, July 2, 2013 at 4:23pm*

**Physics**

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter = 3.000cm = 0.03m Ultimate ...
*Tuesday, July 2, 2013 at 11:49am*

**Physics**

What is the factor of safety of a steel hanger having an ultimate strength of 630.000MPa and supporting a load of 65000.000N. The steel hanger in question has a cross sectional area of 5.300cm. ANS = (Round to 3 decimal places) Load = 65000.000N ultimate strength = 630.000MPa...
*Tuesday, July 2, 2013 at 11:48am*

**physics**

A car travels a distance of 100m per second with a constant acceleration and average velocity of 20m per second .The final velocity acquired by the car is 25m per second .Find The initial velocity and acceleration of car
*Tuesday, July 2, 2013 at 9:44am*

**physics**

A car tavels a distance of 100 m with a constant acceleration and average velocity of 20 m per second .The final velocity acquire D by the car is 25m per second .find the initial velocity and acceleration of car
*Tuesday, July 2, 2013 at 9:42am*

**General physics**

A 34.1 kg child rides a Ferris wheel whose diameter is 18.3 m. When the ride is turning at a constant rate, the child’s speed has a constant value of 4.23 m/s. Find the normal force the seat exerts on the child at: a) The top of the ride b) The bottom of the ride here are...
*Tuesday, July 2, 2013 at 9:39am*

**general physics**

A 13,900 kg truck is moving at 23.5 m/s on a mountain road when the brakes are applied. The brakes FAIL!! Fortunately, the driver sees a deceleration (ouch!) ramp a short distance ahead. This is an incline used by out of control trucks to dissipate their KE by converting it to...
*Tuesday, July 2, 2013 at 9:35am*

**physics**

A car travels a distance of 100m per second with a constant acceleration and average velocity of 20m per second .The final velocity acquired by the car is 25m per second .Find The initial velocity and acceleration of car
*Tuesday, July 2, 2013 at 9:34am*

**physics**

A car travels a distance of 100m per second with a constant acceleration and average velocity of 20m per second .The final velocity acquired by the car is 25m per second .Find The initial velocity and acceleration of car
*Tuesday, July 2, 2013 at 9:33am*

**physics**

scientific interpretation of two toy cars having bar magnet on the roof .what happen when close to each other from same and different direction?
*Tuesday, July 2, 2013 at 7:42am*

**Physics**

A "rocket car" is launched along a long straight track at t=0s. It moves with constant acceleration a1=3.0m/s^2. At t=2.5s, a second car is launched with constant acceleration a2=9.0m/s^2. 1. At what time does the second car catch up with the first one? 2. How far ...
*Tuesday, July 2, 2013 at 1:46am*

**physics**

Two small stereo speakers A and B that are 1.40m apart are sending out sound of wavelength 33.5cm in all directions and all in phase. A person at point P starts out equidistant from both speakers and walks (see the figure (Figure 1) ) so that he is always 1.50m from speaker B...
*Monday, July 1, 2013 at 10:23pm*

**Gen physics**

A 13,900 kg truck is moving at 23.5 m/s on a mountain road when the brakes are applied. The brakes FAIL!! Fortunately, the driver sees a deceleration (ouch!) ramp a short distance ahead. This is an incline used by out of control trucks to dissipate their KE by converting it to...
*Monday, July 1, 2013 at 9:27pm*

**physics**

A 34.1 kg child rides a Ferris wheel whose diameter is 18.3 m. When the ride is turning at a constant rate, the child’s speed has a constant value of 4.23 m/s. Find the normal force the seat exerts on the child at: a) The top of the ride b) The bottom of the ride
*Monday, July 1, 2013 at 7:08pm*

**Physics**

A 13,900 kg truck is moving at 23.5 m/s on a mountain road when the brakes are applied. The brakes FAIL!! Fortunately, the driver sees a deceleration (ouch!) ramp a short distance ahead. This is an incline used by out of control trucks to dissipate their KE by converting it to...
*Monday, July 1, 2013 at 7:07pm*

**general physics**

COMPLETELY STUCK? The period of rotation of the Moon is about 27 days, 8 hrs. The mass of the Moon is 7.35 x 1022 kg, and the radius of the Moon is 1.74 x 106 m. I wish to place a synchronous (period of orbit = period of the Moon’s rotation) satellite in orbit about the ...
*Monday, July 1, 2013 at 5:58pm*

**general physics**

His spacecraft, Vostok I, was a sphere about 2.3 m in diameter, and it reached a maximum altitude above Earth’s surface of 327 km. What was the spacecraft’s speed at this point in its orbit?
*Monday, July 1, 2013 at 5:56pm*

**Physics**

You stand at the end of a long board of length L. The board rests on a frictionless frozen surface of a pond. You want to jump to the opposite end of the board. What is the minimum take-off speed v measured with respect to the pond that would allow you to accomplish that? The ...
*Monday, July 1, 2013 at 5:24pm*

**physics**

Suppose two carts, one twice as massive as the other, fly apart when the compressed spring that joins them is released. How fast does the heavier cart roll compared to the lighter cart?
*Monday, July 1, 2013 at 5:13pm*

**physics**

starting from rest, find a 54.6kg child’s speed at the bottom of a 15.5m tall slide if it is assumed to be frictionless
*Monday, July 1, 2013 at 4:36pm*

**physics**

A 950-kg race car can drive around an unbanked turn at a maximum speed of 46 m/s without slipping. The turn has a radius of 120 m. Air flowing over the car's wing exerts a downward-pointing force (called the downforce) of 12000 N on the car. (a) What is the coefficient of ...
*Monday, July 1, 2013 at 4:27pm*

**physics**

The hammer throw is a track-and-field event in which a 7.30-kg ball (the hammer) is whirled around in a circle several times and released. It then moves upward on the familiar curved path of projectile motion and eventually returns to the ground some distance away. The world ...
*Monday, July 1, 2013 at 4:08pm*

**physics**

the man hanging upside down is holding a partner who weighs 491 N. Assume that the partner moves on a circle that has a radius of 5.09 m. At a swinging speed of 4.20 m/s, what force must the man apply to his partner in the straight-down position?
*Monday, July 1, 2013 at 4:07pm*

**physics**

A person whose weight is 507 N is being pulled up vertically by a rope from the bottom of a cave that is 30.1 m deep. The maximum tension that the rope can withstand without breaking is 590 N. What is the shortest time, starting from rest, in which the person can be brought ...
*Monday, July 1, 2013 at 4:06pm*

**physics**

Two objects (52.0 and 20.0 kg) are connected by a massless string that passes over a massless, frictionless pulley. The pulley hangs from the ceiling. Find (a) the acceleration of the objects and (b) the tension in the string.
*Monday, July 1, 2013 at 3:58pm*

**Physics**

A book weighing 12 N is placed on a table. How much support force does a table exert on the book? Answer in units of N
*Monday, July 1, 2013 at 2:35pm*

**Physics**

A thin aluminum ring hangs vertically from a torsion spring. A torsion spring when twisted exerts a restoring torque given by τ=−κθ where θ is the angle of twist. Suppose that the ring undergoes small torsional oscillations while it is being cooled ...
*Monday, July 1, 2013 at 2:21pm*

**Physics**

Two charges +q and −q are separated by a distance d=50 cm. The electric field lines for this system form the the well-known pattern showed in the figure below. Consider two lines L1 and L2 lying on the same plane and leaving the positive charge at α=±45∘...
*Monday, July 1, 2013 at 2:18pm*

**physics**

The earth rotates once per day about an axis passing through the north and south poles, an axis that is perpendicular to the plane of the equator. Assuming the earth is a sphere with a radius of 6.38 x 106 m, determine the speed and centripetal acceleration of a person ...
*Monday, July 1, 2013 at 1:06pm*

**physics**

Even though we have found an earth sized planet around the nearest star Alpha Centauri B, we're not even close to getting there. To see this let's think about the duration of a flight to Alpha Centauri B, which is about 4×1016 meters away. Imagine a rocket that ...
*Monday, July 1, 2013 at 1:05pm*

**Physics**

A 51.9-g golf ball is driven from the tee with an initial speed of 50.8 m/s and rises to a height of 28.4 m. (a) Neglect air resistance and determine the kinetic energy of the ball at its highest point. (b) What is its speed when it is 6.08 m below its highest point?
*Monday, July 1, 2013 at 12:55pm*

**Physics**

Charged particles such as ions can separate the charges inside of overall electrically neutral atoms, thus making an electric dipole. A dipole is characterized with a dipole moment p=αEexternal, where α is the polarizability of an atom, and Eexternal is the external ...
*Monday, July 1, 2013 at 12:14pm*

**Physics**

What is the factor of safety of a steel hanger having an ultimate strength of 630.000MPa and supporting a load of 65000.000N. The steel hanger in question has a cross sectional area of 5.300cm. ANS = (Round to 3 decimal places) Load = 65000.000N ultimate strength = 630.000MPa...
*Monday, July 1, 2013 at 12:05pm*

**Physics**

The Ultimate strength of a round steel rod is 630.000MPa. If a factor of safety of 5.000 is required, what is the maximum permissible load for the rod if it has a diameter of 3.000cm? ANS = kN (Round to 3 decimal places) Safety = 5.000 Rod diameter = 3.000cm = 0.03m Ultimate ...
*Monday, July 1, 2013 at 12:04pm*

**Physics**

A steel bar has a rectangular cross section measuring 1.000cm by 2.900cm and is 8.700m in length. A load of 189000.00N causes the bar to extend 1.500mm. Calculate the stress and strain produced. ANS 1 = kPa (3 decimal places) ANS 2 = (6 decimal places) 1.000cm = 0.01m 2.900cm...
*Monday, July 1, 2013 at 12:03pm*

**Physics**

A uniform bar 1.000 meters in length and having a cross sectional area of 10.000cm^2 is subjected to a loading of 5750.000 Newtons. This load causes an extension to the bar length of 2.740mm. Calculate the stress and the strain produced. ANS 1 = kPa (Round to 3 decimal places...
*Monday, July 1, 2013 at 12:02pm*

**Physics**

The ultimate strength of a steel rod is 600.000MPa. if the factor of safety 3.000 is required, what is the maximum permissible load for the rod if it has a diameter of 6.000cm? ANS = kN (Round to 3 decimal place) Ultimate strength = 600.000MPa = 600000000Pa = 600 * 10^6 Factor...
*Monday, July 1, 2013 at 12:01pm*

**Physics**

1) Calculate the tensile stress in a 33.000mm diameter rod subjected to a pull of 30.000kN. ANS= MPa (Round to 3 decimal places) Diameter = 33.000mm = 0.033m 30.000kN = 30000N Area = pi*d^2/4 = 3.1416 * 0.033^2/ 4 = 3.1416 *0.001089/ 4 = 0.0034212024/ 4 = 8.553006*10^-4 = 0....
*Monday, July 1, 2013 at 12:00pm*

**Physics**

A rock is ejected vertically upward at 40 m/s. At what time is the rock moving at 20 m/s upward.
*Monday, July 1, 2013 at 10:56am*

**physics**

How long does it take a plane, traveling at a constant speed of 166 m/s, to fly once around a circle whose radius is 4000 m?
*Sunday, June 30, 2013 at 10:47pm*

**physics**

A heavier mass m1 and a lighter mass m2 are 18.0 cm apart and experience a gravitational force of attraction that is 9.70 10-9 N in magnitude. The two masses have a combined value of 5.65 kg. Determine the value of each individual mass.
*Sunday, June 30, 2013 at 10:43pm*

**Physics**

a person jumps from a ledge 3.7 meters and when he drops to the ground it takes .7 meters for him to stop what is the force applied to his body
*Sunday, June 30, 2013 at 10:30pm*

**Physics**

a 3.6 kg object is accelerated from rest to a speed of 34.4 m/s in 42 s. What average force was exerted on the object during this period of acceleration. Answer in units of N.
*Sunday, June 30, 2013 at 6:34pm*

**Physics**

A 3.6 kg object is accelerated from rest to a speed of 34.4 m/s in 42 s. What average force was exerted on the object during this period of acceleration? Answer in units of N
*Sunday, June 30, 2013 at 6:23pm*

**Mechanics/Physics**

HW7_1B_2 : 5.0 POINTS Let's say that a cross section where you have M+max is at location x+max, and the cross section where you have M−max is at location x−max. Use the MATLAB window below to plot the profiles of stress on sections x+max and x−max, i.e...
*Sunday, June 30, 2013 at 5:48pm*

**Physics**

a 3.6 kg object is accelerated from rest to a speed of 34.4 m/s in 42 s. What average force was exerted on the object during this period of acceleration. Answer in units of N.
*Sunday, June 30, 2013 at 5:34pm*

**physics**

Part (a) of the drawing shows a bucket of water suspended from the pulley of a well; the tension in the rope is 69.0 N. Part (b) shows the same bucket of water being pulled up from the well at a constant velocity. What is the tension in the rope in part (b)?
*Sunday, June 30, 2013 at 5:30pm*

**physics**

A man is standing on a platform that is connected to a pulley arrangement, as the drawing shows. By pulling upward on the rope with a force the man can raise the platform and himself. The total mass of the man plus the platform is 94.7 kg. What pulling force should the man ...
*Sunday, June 30, 2013 at 5:29pm*

**Physics**

When switched off, a spinning ceiling fan slows down with an angular acceleration of 1.2 rad/s2. If the fan was spinning at the rate of 10π rad/sec before it was turned off, how many revolutions did it go through before coming to the stop?
*Sunday, June 30, 2013 at 5:24pm*

**Physics**

An object is moving with constant velocity -->v Which situation is impossible in such a circumstance? 1. One force acts on the object. 2. Three forces act on the object. 3. No forces act on the object. 4. Two forces act on the object. 5. Four forces act on the object.
*Sunday, June 30, 2013 at 5:14pm*

**Physics**

Consider a coin which is tossed straight up into the air. After it is released it moves upward, reaches its highest point and falls back down again. Air resistance can be neglected. What force acts upon the coin when it is at its highest point? a. Force acting up and ...
*Sunday, June 30, 2013 at 5:10pm*

**Physics**

a 3.6 kg object is accelerated from rest to a speed of 34.4 m/s in 42 s. What average force was exerted on the object during this period of acceleration. Answer in units of N.
*Sunday, June 30, 2013 at 4:19pm*

**Physics**

Consider a coin which is tossed straight up into the air. After it is released it moves upward, reaches its highest point and falls back down again. Air resistance can be neglected. What force acts upon the coin while it moves upward after it is released? a. Force of zero b. ...
*Sunday, June 30, 2013 at 4:11pm*

**Physics**

A convex mirror form an image of height 2.4cm, if the radius of covature of the mirror is 40cm.find the height,distance of the object from the front of the mirror
*Sunday, June 30, 2013 at 3:29pm*

**PHYSICS 2**

An electron in an x-ray machine is accelerated through a potential difference of 1x10^4 V before it hits the target. What is the kinetic energy of the electron in electron volts?
*Sunday, June 30, 2013 at 3:21pm*

**physics**

A rescue helicopter is lifting a man (weight = 925 N) from a capsized boat by means of a cable and harness. (a) What is the tension in the cable when the man is given an initial upward acceleration of 2.59 m/s2? (b) What is the tension during the remainder of the rescue when ...
*Sunday, June 30, 2013 at 1:22pm*

**physics**

A toboggan slides down a hill and has a constant velocity. The angle of the hill is 6.50° with respect to the horizontal. What is the coefficient of kinetic friction between the surface of the hill and the toboggan?
*Sunday, June 30, 2013 at 1:20pm*

**physics**

A man is standing on a platform that is connected to a pulley arrangement, as the drawing shows. By pulling upward on the rope with a force the man can raise the platform and himself. The total mass of the man plus the platform is 94.7 kg. What pulling force should the man ...
*Sunday, June 30, 2013 at 1:19pm*

**physics**

A block is pressed against a vertical wall by a force , as the drawing shows. This force can either push the block upward at a constant velocity or allow it to slide downward at a constant velocity. The magnitude of the force is different in the two cases, while the ...
*Sunday, June 30, 2013 at 1:18pm*

**physics**

Part (a) of the drawing shows a bucket of water suspended from the pulley of a well; the tension in the rope is 69.0 N. Part (b) shows the same bucket of water being pulled up from the well at a constant velocity. What is the tension in the rope in part (b)?
*Sunday, June 30, 2013 at 1:15pm*

**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 = 56.2 N, W2...
*Sunday, June 30, 2013 at 1:04pm*

**physics**

Three forces act on a moving object. One force has a magnitude of 83.4 N and is directed due north. Another has a magnitude of 47.2 N and is directed due west. What must be (a) the magnitude and (b) the direction of the third force, such that the object continues to move with ...
*Sunday, June 30, 2013 at 1:00pm*

**physics**

A 9.90-kg box is sliding across the horizontal floor of an elevator. The coefficient of kinetic friction between the box and the floor is 0.372. Determine the kinetic frictional force that acts on the box when the elevator is (a) stationary, (b) accelerating upward with an ...
*Sunday, June 30, 2013 at 12:56pm*

**Physics**

A dragster and driver together have mass 929.4 kg. The dragster, starting from rest, attains a speed of 26.5 m/s in 0.55s. Assume the driver has a mass of 77.4 kg. What horizontal force does the seat exert on the driver? Answer in units of N.
*Sunday, June 30, 2013 at 12:10pm*

**physics**

After sliding down a snow-covered hill on an inner tube, Ashley is coasting across a level snowfield at a constant velocity of +2.8 m/s. Miranda runs after her at a velocity of +4.8 m/s and hops on the inner tube. How fast do the two of them slide across the snow together on ...
*Sunday, June 30, 2013 at 11:51am*

**Physics**

A 39.2-kg boy, riding a 2.39-kg skateboard at a velocity of +4.97 m/s across a level sidewalk, jumps forward to leap over a wall. Just after leaving contact with the board, the boy's velocity relative to the sidewalk is 6.48 m/s, 9.54° above the horizontal. Ignore any ...
*Sunday, June 30, 2013 at 11:36am*

**Physics**

A dragster and driver together have mass 929.4 kg. The dragster, starting from rest, attains a speed of 26.5 m/s in 0.55s. What is the size of the average force on the dragster during this time interval? Answer in units of N.
*Sunday, June 30, 2013 at 10:32am*

**Physics**

A dragster and driver together have mass 929.4 kg. The dragster, starting from rest, attains a speed of 26.5 m/s in 0.55s. What is the size of the average force on the dragster during this time interval? Answer in units of N.
*Sunday, June 30, 2013 at 10:31am*

**physics**

A calorie is unit of heat or energy and it equals about 4.2J, where 1J= 1 kgm2/s2. Suppose we employ a system of units in which the unit of mass α kg, the unit of length β m & the unit of time γ s. Show that a calorie has a magnitude of 4.2α-1β-2γ...
*Sunday, June 30, 2013 at 10:27am*

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