Friday

May 29, 2015

May 29, 2015

**Physics**

A frisbee is thrown horizontally with a speed of 12 m/s. If the frisbee moves a horizontal distance of 15 m, how long will it stay in the air?
*Saturday, March 7, 2015 at 9:55pm*

**physics**

A black and tackle with a velocity ratio of 5 is used to raise a mass of 25kg through a vertical distance of 40cm at a steady rate.if the effort is equal to 60N, determine a. The distance moved by the effort b. The work done by the effort in lifting the load
*Saturday, March 7, 2015 at 3:07pm*

**physics**

skater has a mass of 45 kg and is at rest. skater 2 has a mass of 50 kg and is moving along at a constant velocity of 3.2 m/s East. skater 3 has a mass of 75 kg and is moving quickly at a constant velocity of 9.6 m/s East. which state experiences the greatest force?
*Saturday, March 7, 2015 at 1:22pm*

**physics**

A car A is going north-east at 80km/h and another car B is going south-east at 60km/h. The direction of the relative velocity of A with B makes an angle of x with north find x
*Saturday, March 7, 2015 at 8:24am*

**physics**

A billiard ball moving at 4.0 m/s strikes a pair of billiard ball at rest. One of the ball moves off at 2.0 m/s in a direction 60 degrees from the line of motion of the first ball and the other moves off at 3.0 m/s in a direction 30 degrees from the line of the first ball on ...
*Saturday, March 7, 2015 at 5:55am*

**physics **

a brass rod is 2 m long at a certain temperature. what is its length for a temperature rise of 100 K, if the expansivity of brass is 18 *10^-6K-1?
*Saturday, March 7, 2015 at 5:30am*

**physics**

A body accelerate from rest at (2m/s square) calculate its velocity after travelling 9m
*Saturday, March 7, 2015 at 4:57am*

**physics**

wo vectors A⃗ and B⃗ have magnitude A = 3.02 and B = 3.03. Their vector product is A⃗ ×B⃗ = -5.05k^ + 2.06 i^. What is the angle between A⃗ and B⃗ ?
*Saturday, March 7, 2015 at 4:03am*

**Physics**

Kaitlin is going off to her physics class, jogging down the sidewalk at a speed of 3.30m/s . Her husband Scott suddenly realises that she left in such a hurry that she forgot her sandwich, so he runs to the window of their apartment, which is a height 35.0m above the street ...
*Saturday, March 7, 2015 at 3:32am*

**Physics**

A car comes to a bridge during a storm and finds the bridge washed out. The driver must get to the other side, so he decides to try leaping it with his car. The side the car is on is 19.5m above the river, while the opposite side is a mere 1.6m above the river. The river ...
*Saturday, March 7, 2015 at 3:24am*

**Physics**

A 7500kg rocket blasts off vertically from the launch pad with a constant upward acceleration of 2.20m/s2 and feels no appreciable air resistance. When it has reached a height of 595m , its engines suddenly fail so that the only force acting on it is now gravity. [1]What is ...
*Saturday, March 7, 2015 at 3:22am*

**physics**

A rigid tank having a volume of 0.100 m3 contains helium gas at 155 atm. How many balloons can be inflated by opening the valve at the top of the tank? Each filled balloon is a sphere 0.300 m in diameter at an absolute pressure of 1.15 atm. (Remember that the tank cannot be ...
*Saturday, March 7, 2015 at 12:28am*

**physics**

A transformer has N1=709turns in the primary coil and N2=1848turns in the secondary coil. If the input voltage is v(t)=218cos(Ωt) V, what rms voltage, in volts, is developed across the secondary coil?
*Friday, March 6, 2015 at 10:59pm*

**physics**

An inductor (L=440mH), a capacitor (C=6.00μF), and a resistor (R=440Ω) are connected in series. A 75.0Hz ac generator produces a peak current of 255mA in the circuit. a) What is the impedance of the circuit? Answer in units of Ω
*Friday, March 6, 2015 at 10:28pm*

**physics**

A 30.0μF capacitor is connected to an ac voltage source with an rms voltage of 150V and a frequency of 2.49KHz. What is the capacitive reactance of the circuit? Assume that there is no resistance in the circuit, and answer in units of ohms
*Friday, March 6, 2015 at 9:23pm*

**physics**

Consider a purely inductive ac circuit in which the maximum voltage across the inductor is Vmax=98.0V. If the maximum current is 7.40A at 40.0Hz, what is the inductance L? Answer in mH.
*Friday, March 6, 2015 at 9:11pm*

**physics**

At what force would a 16k object travelling at 25mph hit a stationery object
*Friday, March 6, 2015 at 8:59pm*

**physics**

a 10-kg block on a perfectly smooth horizontal table is connected by a horizontal string to a 63-kg block that is hanging over the edge of the table. What is the magnitude of the acceleration of the 10-kg block when the other block is gently released?
*Friday, March 6, 2015 at 6:37pm*

**math, physics**

The driver of a car traveling at 60 ft/sec suddenly applies the brakes. The position of the car is s(t) equals 60t minus - 1.5t^2, t seconds after the driver applies the brakes. How many seconds after the driver applies the brakes does the car come to a stop?
*Friday, March 6, 2015 at 6:11pm*

**Physics**

A person walks first at a constant speed of 4.50 m/s along a straight line from point circled A to point circled B and then back along the line from circled B to circled A at a constant speed of 2.95 m/s. What is her average speed over the entire trip? I got 3.7 but it says it...
*Friday, March 6, 2015 at 4:27pm*

**physics **

A charge q1 is inside a spherical surface (although not necessarily at the exact center of the sphere). A second charge q2 sits just outside the surface. Choose whether the following statements are true or false. T/F The total electric flux through the spherical surface ...
*Friday, March 6, 2015 at 1:59pm*

**physics**

A skier starts from rest at the top of a frictionless incline of height 20.0 m, as shown in the figure. At the bottom of the incline, the skier encounters a horizontal surface where the coefficient of kinetic friction between skis and snow is 0.208. Neglect air resistance.Find...
*Friday, March 6, 2015 at 1:06pm*

**physics**

A diver of mass m drops from a board 12.0 m above the water's surface, as shown in the figure. Neglect air resistance. Suppose the diver vaults off the springboard, leaving it with an initial speed of 3.96 m/s upward. Use energy conservation to find his speed when he ...
*Friday, March 6, 2015 at 12:38pm*

**Physics**

a siren has a frequency of 1099 Hz when it and an observer are both at rest. The observer then starts to move and finds that the frequency he hears is 1185 Hz. What is the speed of the observer?
*Friday, March 6, 2015 at 12:21pm*

**Physics 1**

A man opens a 1.14-m wide door by pushing on it with a force of 49.5 N directed perpendicular to its surface. (a) What magnitude torque does he apply about an axis through the hinges if the force is applied at the center of the door? N · m (b) What magnitude torque does...
*Friday, March 6, 2015 at 12:21pm*

**Physics 1**

A bicycle tire has a mass of 2.54 kg and a radius of 0.346 m. (a) Treating the tire as a hoop, what is its moment of inertia about an axis passing through the hub at its center? kg · m2 (b) What torque is required to produce an angular acceleration of 0.710 rad/s2? N &...
*Friday, March 6, 2015 at 12:19pm*

**Physics **

A bowling ball of mass 7.45 kg is rolling at 2.56 m/s along a level surface. (a) Calculate the ball's translational kinetic energy. J (b) Calculate the ball's rotational kinetic energy. J (c) Calculate the ball's total kinetic energy. J (d) How much work would have...
*Friday, March 6, 2015 at 12:17pm*

**Physics **

A spinning wheel steadily slows from an initial angular velocity of 1.65 rev/s to 0.485 rev/s in 12.2 s. (a) Calculate the wheel's angular acceleration in radians per second squared. rad/s2 (b) What angle does it go through during that time? rad
*Friday, March 6, 2015 at 12:08pm*

**AP physics **

Solve the equations 1/2mv2 + 1/2Iω2 = mgh and v = rω for the speed v using substitution, given that I = mr2 and h = 4.20 m. (Note that mass m and radius r will both cancel, so their numerical values aren't required.) m/s
*Friday, March 6, 2015 at 11:56am*

**Ap physics**

The two conditions for equilibrium often result in a system of equations such as F1 + F2 = 44.0 N and 3.00F1 − 8.00F2 = 0. (Due to the nature of this problem, do not use rounded intermediate values in your calculations—including answers submitted in WebAssign.) (a) ...
*Friday, March 6, 2015 at 11:54am*

**physics**

A student, 90.0 m away from the foot of a cliff, claps her hands and hears the echo 0.50 s later. Calculate the speed of sound in the air.
*Friday, March 6, 2015 at 10:11am*

**Physics**

Carl hits a 0.05 kg golf ball giving it a speed of 65 m/s. What impulse does he impact to the ball?
*Friday, March 6, 2015 at 4:28am*

**Physics**

A car that slows down uniformly from 20 m/s to 5 m/s has an impulse of 30,000 kg m/s. Determine the mass of the car
*Friday, March 6, 2015 at 4:28am*

**Physics**

A Frisbee is thrown horizontally with a speed of 12 m/s. If the Frisbee moves a horizontal distance of 15 m, how long will it stay in the air?
*Friday, March 6, 2015 at 4:28am*

**Physics**

An orange rolls across a table with a speed of 0.5 m/s and falls off the edge. If it lands 3 m from the edge of the table, from what height does it fall?
*Friday, March 6, 2015 at 4:28am*

**Physics**

A package is dropped from a helicopter flying at a height of 7.5 m while traveling 15 m/s. How far is the package travel horizontally before it hits the ground below?
*Friday, March 6, 2015 at 4:28am*

**Physics**

A gardener holds a hose 0.75 m above the ground such that water shoots out horizontally and hits the ground at a point 2 m away. What is the speed with which the water leaves the hose?
*Friday, March 6, 2015 at 4:27am*

**physics**

A disk of mass m is spinning freely at 6.22 rad/s when a second disk of identical mass, initially not spinning, is dropped on it so that their axes coincide. In a short time the two disks are corotating. (The two disks have the same radius.) (a) What is the angular speed of ...
*Friday, March 6, 2015 at 12:16am*

**physics**

A basketball player entertains the crowd by spinning a basketball on his nose. The basketball has a mass of 0.622 kg and a radius of 0.116 m. If the basketball is spinning at a rate of 7.00 revolutions per second, determine the following. Treat the ball as a thin, spherical ...
*Friday, March 6, 2015 at 12:16am*

**physics**

A bowling ball of mass 7.45 kg is rolling at 2.56 m/s along a level surface. (a) Calculate the ball's translational kinetic energy. J (b) Calculate the ball's rotational kinetic energy. J (c) Calculate the ball's total kinetic energy. J (d) How much work would have...
*Friday, March 6, 2015 at 12:16am*

**physics**

A bicycle tire has a mass of 2.54 kg and a radius of 0.346 m. (a) Treating the tire as a hoop, what is its moment of inertia about an axis passing through the hub at its center? kg · m2 (b) What torque is required to produce an angular acceleration of 0.710 rad/s2? N &...
*Friday, March 6, 2015 at 12:15am*

**physics**

What is the magnitude of the angular acceleration of a 25.5-kg disk of radius 0.775 m when a torque of magnitude 41.5 N · m is applied to it? rad/s2
*Friday, March 6, 2015 at 12:15am*

**physics**

A student rides his bicycle at a constant speed of 2.20 m/s along a straight, level road. If the bike's tires each have a radius of 0.338 m, determine the following. (a) What is the tires' angular speed? rad/s (b) What is the net torque on each tire? N · m
*Friday, March 6, 2015 at 12:15am*

**physics**

A horizontal plank 4.12 m long and having mass 26.8 kg rests on two pivots, one at the left end and a second 1.03 m from the right end. Find the magnitude of the force exerted on the plank by the second pivot. N
*Friday, March 6, 2015 at 12:14am*

**physics**

A mass of 1.50 kg is at (−2.55 m, 0) and a 2.04-kg mass at (4.00 m, 4.00 m). Find the center of mass of the system. ( m, m)
*Friday, March 6, 2015 at 12:14am*

**physics**

A worker applies a torque to a nut with a wrench 0.485 m long. Because of the cramped space, she must exert a force upward at an angle of 57.0° with respect to a line from the nut through the end of the wrench. If the force she exerts has magnitude 81.5 N, what magnitude ...
*Friday, March 6, 2015 at 12:11am*

**physics**

A man opens a 1.14-m wide door by pushing on it with a force of 49.5 N directed perpendicular to its surface. (a) What magnitude torque does he apply about an axis through the hinges if the force is applied at the center of the door? N · m (b) What magnitude torque does...
*Friday, March 6, 2015 at 12:04am*

**physics**

A construction crane's cable lifts a 49.5-kg box upward with an acceleration of 1.30 m/s2. Find the tension in the rope. N
*Friday, March 6, 2015 at 12:04am*

**physics**

A spinning wheel steadily slows from an initial angular velocity of 1.65 rev/s to 0.485 rev/s in 12.2 s. (a) Calculate the wheel's angular acceleration in radians per second squared. rad/s2 (b) What angle does it go through during that time? rad
*Friday, March 6, 2015 at 12:03am*

**physics**

Solve the equations 1 2 mv2 + 1 2 Iω2 = mgh and v = rω for the speed v using substitution, given that I = mr2 and h = 4.20 m. (Note that mass m and radius r will both cancel, so their numerical values aren't required.)
*Friday, March 6, 2015 at 12:02am*

**physics**

The two conditions for equilibrium often result in a system of equations such as F1 + F2 = 44.0 N and 3.00F1 − 8.00F2 = 0. find F1 and find F2
*Friday, March 6, 2015 at 12:02am*

**physics**

A painter is pressing a 125g paint pad against the ceiling with a force of 8.3 N at an angle of 30° from the vertical. The pad moves at a constant velocity. What is the coefficient of friction between the pad and ceiling?
*Thursday, March 5, 2015 at 11:07pm*

**physics**

A turntable turning at rotational speed 21rpm stops in 50s when turned off. The turntable's rotational inertia is 1.2×10−2kg⋅m2. a)Determine the magnitude of the resistive torque that slows the turntable.
*Thursday, March 5, 2015 at 10:04pm*

**physics **

The sweeping second hand on your wall clock is 24cm long. a)What is the rotational speed of the second hand? b)Find the translational speed of the tip of the second hand. c)Find the rotational acceleration of the second hand.
*Thursday, March 5, 2015 at 10:03pm*

**physics**

What mechanical work must you do to lift a uniform log that is 3.3m long and has a mass of 100kg from the horizontal to a vertical position? [Hint: Use the work-energy principle.]
*Thursday, March 5, 2015 at 10:01pm*

**Physics**

A simple wheel and axle is used to life a bucket out of a well. The radii of the wheel and axle are 20 cm and 4 cm, respectively. Determine: 1. The velocity ratio (and so the IMA), 2. The thoretical effort required to life a load of 30 N assuming no energy loosses, 3. The ...
*Thursday, March 5, 2015 at 9:48pm*

**Physics**

An explosion breaks an object initially at rest into two pieces, one of which has 2.0 times the mass of the other. If 7300 J of kinetic energy were released in the explosion, how much kinetic energy did the lighter piece acquire?
*Thursday, March 5, 2015 at 9:45pm*

**Physics**

A cue ball traveling at 0.70 m/s hits a stationary 8-ball, which moves off with a speed of 0.23 m/s at an angle of 39° relative to the cue ball's initial direction. Assuming that the balls have equal masses and the collision is inelastic, at what angle will the cue ...
*Thursday, March 5, 2015 at 9:44pm*

**Physics **

Object A is moving due east, while object B is moving due north. They collide and stick together in a completely inelastic collision. Momentum is conserved. Object A has a mass of mA = 17.0 kg and an initial velocity of VoA = 8.15 m/s, due east. Object B, however, has a mass ...
*Thursday, March 5, 2015 at 9:43pm*

**Physics**

During a workout, the football players at Rutgers State University ran up the stadium stairs at a steady pace in 48 s. The stairs are 135 m long and inclined at an angle of 35 degree. If a typical player has a mass of 120 kg, estimate the average power output on the way up. ...
*Thursday, March 5, 2015 at 9:42pm*

**Physics**

A car of mass 1490 kg traveling at 22 m/s is at the foot of a hill that rises 115 m in 3.2 km. At the top of the hill, the speed of the car is 12 m/s. Find the average power delivered by the car's engine, neglecting any frictional losses.
*Thursday, March 5, 2015 at 9:41pm*

**Physics**

1.For the following simple see-saw calculate: 1. the load that could be lifed, 2. the maechanical advantage (assume the lever is 100% efficient).
*Thursday, March 5, 2015 at 9:35pm*

**Physics**

A transverse wave 1.1cm in amplitude is propagating on a string; the wave frequency is 44 Hz. The string is under 23-N tension and has mass per unit length of 16g/m . What is the wave speed? What I've done: using sqrt(Tension/mass_per_unit): sqrt(23/16)=1.19m/s But not ...
*Thursday, March 5, 2015 at 9:33pm*

**Physics (Kinematics)**

In a television tube, the electron travels from an electron gun to the screen 0.45m away in 6.0×10exponent-9seconds. If the electron starts at rest, what is its final speed when it hots the screen? ( I have the answer,but I don't know how to get it)
*Thursday, March 5, 2015 at 6:23pm*

**physics**

a sound wave of frequency 1.2hz is reflected from a barrier 75m away and its receiver 0.5 sec after transmission.calculate the wave length of the sound
*Thursday, March 5, 2015 at 5:29pm*

**Physics**

An echo in Cowboys Stadium is heard after 2 seconds. How far is the person standing from the wall if the speed of sound is 340 m/sec?
*Thursday, March 5, 2015 at 4:03pm*

**Physics**

The speed of a wave doubles as it passes from one medium to the next. How will this affect the frequency of the wave?
*Thursday, March 5, 2015 at 3:59pm*

**Physics**

a man sets his watch at noon by the sound of a factory whistle 4.8 km away. If the temperature of the air is 20 degrees C, how many seconds slow will his watch be?
*Thursday, March 5, 2015 at 3:45pm*

**physics**

Your car rides on springs, so it will have a natural frequency of oscillation. (Figure 1) shows data for the amplitude of motion of a car driven at different frequencies. The car is driven at 24mph over a washboard road with bumps spaced 12 feet apart; the resulting ride is ...
*Thursday, March 5, 2015 at 2:20pm*

**physics**

The power output in the sun is about 4.00 x 10^26W. (a). Calculate the power per unit area (intensity), in kilowatts per square meter, reaching Earth's upper atmosphere from the sun. The radius of the Earth's orbit is 1.5 x 10^11m.
*Thursday, March 5, 2015 at 12:35pm*

**physics**

A police car is traveling at a constant velocity 18 m/s north, when a car zooms by at a constant velocity 42 m/sÂ due north. After a reaction time of 0.8 s the police car pursue the speeder with an acceleration of 5 m/s2. How long (in s) does it take for the police car ...
*Thursday, March 5, 2015 at 11:56am*

**Physics**

A 150 gram golden (specific heat 0.03 cal/gram^0 C) spoon at 20^0C is placed in a cup of tea at 100^0C. The amount of heat which the spoon absorbs from the tea which is necessary to reach spoon's tempature 47^0C is a)360.4 Cal b)121.5 Cal c)78.24 Cal d)15.08 Cal e)157.5 Cal
*Thursday, March 5, 2015 at 11:41am*

**Physics**

The force between positive charges from the problem 18) has the magnitude a)4 Newtons b)9 Newtons c)9x10^9 Newtons d)4x10^9 Newtons e)none of these
*Thursday, March 5, 2015 at 11:37am*

**Physics**

Two positive charges of +2 coulombs are 3 meters apart. If one of the charges is replaced by the negative charge -2 coulombs, the magnitude of force between them is: a)larger b)smaller c)the same d)zero e)none of these
*Thursday, March 5, 2015 at 11:34am*

**Physics**

I need help with the second part of this question. Please show work so I can see. Thanks. I. The fastest land mammal, the cheetah, can accelerate from 0 mi/hr to 70.0 mi/hr in 3.0 seconds. What is the acceleration of the cheetah? Give your answer in units of mph/sec. I got 23....
*Thursday, March 5, 2015 at 11:30am*

**physics**

This green box, which has a mass of 500 kg, is hanging from the ceiling by two ropes. However, it's not quite centered correctly. Angle θ1=20.8 degrees and angle θ2=30.8 degrees. What is the tension in Rope # 2?
*Thursday, March 5, 2015 at 10:57am*

**Physics**

A plane traveling at 200.0 km/h attempts to land on a 250 m runway. The plane’s engines and brakes accelerate uniformly at –7.0 m/s2. Will the plane be able to land safely? Show all your work. Include any equations used, including the given and the unknown. Show all ...
*Thursday, March 5, 2015 at 10:35am*

**physics**

A sled is moving at a constant speed down a surface inclined at 45.0° with the horizontal and travels 30 meters in 4 seconds. Calculate the vertical velocity of the sled at the end of 4 seconds.
*Thursday, March 5, 2015 at 10:21am*

**physics**

An inclined plane rises to aheight of 2 m over adistance of 6 m. Calculate: 1.The ange of the slope 2.The VR (and so IMA) of the inclined plane. 3The theoretical force required to push an object with a mass of 200 Kg up the slope.
*Thursday, March 5, 2015 at 8:07am*

**physics**

A child on a beach tosses a walnut straight upward. it reaches the peak of its trajectory and then falls straight downward retracing its path when a hungry seagull grabs the walnut 10.1m above the release point at a time of 1.6s after it was thrown. find the initial velocity ...
*Thursday, March 5, 2015 at 12:31am*

**Physics**

A mechanical device requires 420 J of work to do 230 J of work in lifting a crate. What is the efficiency of the device? I keep getting 0.5% am I right?
*Wednesday, March 4, 2015 at 11:51pm*

**physics**

4.) A 8.0 kilogram physics textbook experiences an applied force of 28.0 Newtons for 2.6 seconds. The resulting acceleration is 3.50 m/s2. Determine the change in the momentum of the book.
*Wednesday, March 4, 2015 at 10:29pm*

**physics**

A radio station is broadcasting at 90.7 mhz. compute for its wavelength in angstrom and energy in kilojoules.
*Wednesday, March 4, 2015 at 10:03pm*

**Physics**

A rocket moves upward, starting from rest with an acceleration of 26.3 m/s2 for 5.43 s. It runs out of fuel at the end of the 5.43 s but does not stop. How high does it rise above the ground?
*Wednesday, March 4, 2015 at 9:33pm*

**Physics**

Calculate the energy released when 235 U fissions resulting in two lighter stable nuclei with mass numbers 140 and 93.Please help!
*Wednesday, March 4, 2015 at 9:15pm*

**Physics**

A 2.8 kg block is pushed a distance D = 9.8 meters at a constant velocity by a force F = 46 N at an angle A = 30. It takes 8.1 seconds to move the block. Friction can be ignored. What is the work done on the block by the force?
*Wednesday, March 4, 2015 at 7:49pm*

**Physics **

A worker applies a torque to a nut with a wrench 0.430 m long. Because of the cramped space, she must exert a force upward at an angle of 59.5° with respect to a line from the nut through the end of the wrench. If the force she exerts has magnitude 81.0 N, what magnitude ...
*Wednesday, March 4, 2015 at 3:07pm*

**physics**

A man opens a 1.19-m wide door by pushing on it with a force of 54.5 N directed perpendicular to its surface. (a) What magnitude torque does he apply about an axis through the hinges if the force is applied at the center of the door? ___N · m (b) What magnitude torque ...
*Wednesday, March 4, 2015 at 3:06pm*

**Physics **

A construction crane's cable lifts a 59.5-kg box upward with an acceleration of 1.38 m/s^2. Find the tension in the rope. 501.585 is incorrect.
*Wednesday, March 4, 2015 at 3:05pm*

**physics**

Find the net torque on the wheel in the figure below about the axle through O perpendicular to the page, taking a = 5.00 cm and b = 23.0 cm. (Indicate the direction with the sign of your answer. Assume that the positive direction is counterclockwise.) f1= 10 f2= 9 f3=12
*Wednesday, March 4, 2015 at 3:02pm*

**physics**

a bus is travelling on a horizontal road at a velocity of 126 km/h when the bus driver notices an object in the road. the brakes are applied and the bus is brought to rest over a distance of 150m. the frictional resistance is 2500n and the bus has a mass of 6000 kg. calculate ...
*Wednesday, March 4, 2015 at 11:27am*

**Physics**

3. Think about this pulling scenario: A 60 N force pulls three boxes across a surface with no friction. T1 is the tension force the rope on the left pulls with at both ends, and T2 is the force the rope on the right pulls with on both ends. (a) Draw diagrams of the three boxes...
*Wednesday, March 4, 2015 at 11:08am*

**physics**

7. A cart like the one we use in lab accelerates down a 20° incline (and since the wheels are smooth, ignore friction for now). Break the force of gravity into components (leave mass as m for now), find the cart’s acceleration, and determine how long it should take ...
*Wednesday, March 4, 2015 at 11:06am*

**physics**

a parent pushes a kid on a swing, A) If the child on the swing rises 2m above the lowest point during each cycle, what is her speed at the lowest point of the swing? B)If the beginning of a cycle (2m above the lowest point) the child is given a push so that her starting speed ...
*Wednesday, March 4, 2015 at 10:56am*

**Physics**

A driver of a car going 90 km/h suddenly sees the lights of a barrier 40.0 m ahead. It takes the driver 0.75 s to apply the brakes, and the average acceleration during braking is -10 m/s2. (a) Compute for the total displacement of the car to determine whether the car hits the ...
*Wednesday, March 4, 2015 at 10:45am*

**Calculus Physics**

A glass of orange juice is on the floor of a subway car traveling along a straight path at constant velocity. Everything's fine. The coefficient of static friction between the glass and the floor is 0.32. The subway suddenly accelerates forward. What is the maximum ...
*Wednesday, March 4, 2015 at 9:16am*

**Physics**

A baseball player with a mass of 79 kg slides into homeplate. The coefficient of kinetic friction between the player and the ground is μk = 0.632. If the player comes to rest after 1.04 s, what is his initial speed?
*Wednesday, March 4, 2015 at 9:15am*

**physics**

In a relay race, each contestant runs a distance 25.7m while carrying an egg balanced on a spoon, turns around, and comes back to the starting point. Jenny runs the first distance 25.7m in a time t1 = 20.0s . On the return trip she is more confident and takes only time t2 = 14...
*Wednesday, March 4, 2015 at 7:23am*

**Physics**

Energy Budget for a Rocket in Free Space: Recall the analysis of the rocket engine in Project I, Flight of the Rocket. Although the momentum of the rocket and its exhaust is conserved (constant), their energy is not; energy must be supplied by the combustion of fuel. WARNING: ...
*Wednesday, March 4, 2015 at 4:28am*

**Physics**

Bob starts spinning his hammer at a rate of 2.00 rad/s^2. At the same time, he starts running towards Jim at 4.00 m/s^2. The distance from the end of the hammer to Bob's elbow is 1.20 m. If Bob takes 3 seconds before he launches the hammer at Jim, what is the resultant ...
*Wednesday, March 4, 2015 at 2:32am*