# Posts by winterWX

Total # Posts: 32

**Re: Physics - drwls #2**

Posted by winterWX on Monday, March 19, 2007 at 11:54pm. A small block of mass m = 4.0 kg can slide along the frictionless loop-the-loop. The block is released from rest at point P, at height h = 23R above the bottom of the loop (R is the radius of the loop). Express your ...

*March 22, 2007*

**Physics - drwls**

Posted by winterWX on Monday, March 19, 2007 at 11:51pm. A 2600 kg truck traveling north at 38 km/hr turns east and accelerates to 55 km/hr. What is the change in the truck's kinetic energy? What is the magnitude of the change in the linear momentum of the truck? What is ...

*March 22, 2007*

**Physics - drwls?**

A small block of mass m = 4.0 kg can slide along the frictionless loop-the-loop. The block is released from rest at point P, at height h = 23R above the bottom of the loop (R is the radius of the loop). Express your answers in the form ngR, where n is the number you will ...

*March 19, 2007*

**Physics - drwls?**

A 2000 kg truck traveling north at 38 km/hr turns east and accelerates to 55 km/hr. What is the change in the truck's kinetic energy? What is the magnitude of the change in the linear momentum of the truck? What is the direction of the change in linear momentum of the ...

*March 19, 2007*

**physics - drwls?**

The flywheel of a steam engine runs with a constant angular speed of 250 rev/min. When steam is shut off, the friction of the bearings stops the wheel in 2.1 h. At the instant the flywheel is turning at 75 rev/min, what is the tangential component of the linear acceleration of...

*March 13, 2007*

**physics**

The flywheel of a steam engine runs with a constant angular speed of 250 rev/min. When steam is shut off, the friction of the bearings stops the wheel in 2.1 h. At the instant the flywheel is turning at 75 rev/min, what is the tangential component of the linear acceleration of...

*March 12, 2007*

**physics - drwls?**

A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 7 rev/s. 55 revolutions later, its angular speed is 21 rev/s. (a) Calculate the angular acceleration. (b) Calculate the time required to ...

*March 12, 2007*

**physics**

A disk rotates about its central axis starting from rest and accelerates with constant angular acceleration. At one time it is rotating at 7 rev/s. 55 revolutions later, its angular speed is 21 rev/s. (a) Calculate the angular acceleration. (b) Calculate the time required to ...

*March 11, 2007*

**physics**

The angular position of a point on the rim of a rotating wheel is given by = 4.0t - 1.0t2 + t3, where is in radians and t is in seconds. (a) What is the angular velocity at t = 2 s? (b)What is the angular velocity at t = 4.0 s? (c) What is the average angular acceleration for ...

*March 10, 2007*

**PHYSICS - still cant get it**

A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of 17 m/...

*February 24, 2007*

**PHYSICS!!!**

A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of 17 m/s...

*February 24, 2007*

**Re: Physics/Math**

A 0.30-kg softball has a velocity of 12 m/s at an angle of 30° below the horizontal just before making contact with the bat. What is the magnitude of the change in momentum of the ball while it is in contact with the bat if the ball leaves the bat with a velocity of 17 m/s...

*February 24, 2007*

**Physics**

An old Chrysler with mass 1900 kg is moving along a straight stretch of road at 48 km/h. It is followed by a Ford with mass 1500 kg moving at 65 km/h. How fast is the center of mass of the two cars moving? m1v1 + m2v2= (m1+m2)vcm solve for vcm 55.5

*February 21, 2007*

**Physics**

A 5.60-kg particle has the xy coordinates (-1.20 m, 0.500 m), and a 5.20-kg particle has the xy coordinates (0.600 m, -0.750 m). Both lie on a horizontal plane. At what x and y coordinates must you place a 1.60-kg particle such that the center of mass of the three-particle ...

*February 21, 2007*

**Physica**

A 21.0-kg satellite has a circular orbit with a period of 2.37 h and a radius of 8.50×106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 7.10 m/s2, what is the radius of the planet? I am not sure ...

*February 17, 2007*

**Physics**

What linear speed must an Earth satellite have to be in a circular orbit at an altitude of 186 km? What is the period of revolution? winterWX, Friday, February 16, 2007 at 9:36pm So GMm/r^2 = mv^2/r and I know that I need to solve for v but what do I use for the mass of the ...

*February 16, 2007*

**Physics**

A 21.0-kg satellite has a circular orbit with a period of 2.37 h and a radius of 8.50×106 m around a planet of unknown mass. If the magnitude of the gravitational acceleration on the surface of the planet is 7.10 m/s2, what is the radius of the planet? Use Kepler's ...

*February 16, 2007*

**Physics**

A orbiting satellite stays over a certain spot on the equator of (rotating) Earth. What is the altitude of the orbit (called a "synchronous orbit")? Write the equation for the period of a satellite in terms of the distance from the Earth's center. It is a special...

*February 16, 2007*

**Physics**

What linear speed must an Earth satellite have to be in a circular orbit at an altitude of 186 km? What is the period of revolution? So GMm/r^2 = mv^2/r and I know that I need to solve for v but what do I use for the mass of the satellite? Do I just plug in values for G, M, m ...

*February 16, 2007*

**Physics**

A star of mass 2.0 1028 kg that is 1.6 1020 m from the center of a galaxy revolves around that center once every 3.4 108 years. Assuming that this star is essentially at the edge of the galaxy, each of the stars in the galaxy has a mass equal to that of this star, and the ...

*February 16, 2007*

**Re: Physics**

A square of edge length 19.0 cm is formed by four spheres of masses m1 = 6.00 g, m2 = 3.50 g, m3 = 1.00 g, and m4 = 6.00 g. In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5 = 2.20 g? _N i + _N j Physics - bobpursley, ...

*February 15, 2007*

**Physics**

In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you weigh 600 N, to ...

*February 14, 2007*

**Physics**

A square of edge length 19.0 cm is formed by four spheres of masses m1 = 6.00 g, m2 = 3.50 g, m3 = 1.00 g, and m4 = 6.00 g. In unit-vector notation, what is the net gravitational force from them on a central sphere with mass m5 = 2.20 g? _N i + _N j You have to put the ...

*February 13, 2007*

**Physics**

A solid uniform sphere has a mass of 2.0 104 kg and a radius of 1.5 m. What is the magnitude of the gravitational force due to the sphere on a particle of mass m = 0.2 kg located at a distance of 1.6 m from the center of the sphere? What if it is 1.1 m from the center of the ...

*February 13, 2007*

**Physics**

In 1956, Frank Lloyd Wright proposed the construction of a mile-high building in Chicago. Suppose the building had been constructed. Ignoring Earth's rotation, find the change in your weight if you were to ride an elevator from the street level, where you weigh 600 N, to ...

*February 13, 2007*

**Physics/Math**

After flying for 15 min in a wind blowing 42 km/h at an angle of 30° south of east, an airplane pilot is over a town that is 50 km due north of the starting point. What is the speed of the airplane relative to the air? This is a vector equation. I would do it graphically. ...

*February 3, 2007*

**Physics/Math**

A boy whirls a stone in a horizontal circle of radius 1.2 m and at height 2.0 m above ground level. The string breaks, and the stone flies horizontally and strikes the ground after traveling a horizontal distance of 10 m. What is the magnitude of the centripetal acceleration ...

*February 3, 2007*

**Physics/Math**

A person walks up a stalled 20 m long escalator in 79 s. When standing on the same escalator, now moving, the person is carried up in 60 s. How much time would it take that person to walk up the moving escalator? ratewalking= 20/79 ratemoving=20/60 time= distance/added rates ...

*February 3, 2007*

**Math/Physics**

A golf ball is struck at ground level. The speed of the golf ball as a function of the, where t = 0 at the instant the ball is struck and intial velocity is 31 m/s. The golf ball hits the ground when t = 2.5 and v = 19, and then v increases as the ball rises back into the air...

*February 1, 2007*

**Math/Physics**

The velocity v of a particle moving in the xy plane is given by v = (6.0t - 4.0t2) i + 4.0 j, with v in meters per second and t (> 0) is in seconds. What is the acceleration when t = 3.0 seconds? When is the acceleration zero? When is the velocity zero? When does the speed ...

*February 1, 2007*

**Math/Physics**

An electron's position is given by r = 4.00t i - 6.00t^2 j + 5.00 k, with t in seconds and r in meters. In unit-vector notation, what is the electron's velocity? (Answer in terms of i, j, k, t.)What is v in unit-vector notation at t = 8 seconds? What is the magnitude ...

*February 1, 2007*

**Math/Physics**

A ball rolls horizontally off the edge of a tabletop that is 1.60 m high. It strikes the floor at a point 1.58 m horizontally away from the table edge. (Neglect air resistance.)How long was the ball in the air? What was its speed at the instant it left the table? The time in ...

*February 1, 2007*

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