Saturday

December 20, 2014

December 20, 2014

Total # Posts: 127

**Physics**

A man (weighing 915 N) stands on a long railroad flatcar (weighing 2805 N) as it rolls at 18.0 m/s in the positive direction of an x axis, with negligible friction. Then the man runs along the flatcar in the negative x direction at 40.00 m/s relative to the flatcar. What is ...
*February 25, 2007*

**Re: Physics/Math**

At time t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is (9.00i + 8.00j) m/s^2. It moves at constant speed. At time t2 = 3.00s (3/4 of a revolution later), it's acceleration is (8.00i - 9.00j) m/s^2. Find the radius of the path taken by ...
*February 18, 2007*

**Re: Physics/Math**

A sphere of mass 2.7 x 10^-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 41 degrees with the vertical. Find the magnitude of the push provided by the breeze and Find the tension in the cord. you have a ...
*February 18, 2007*

**Physics/Math**

A sphere of mass 2.7 x 10^-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 41 degrees with the vertical. Find the magnitude of the push provided by the breeze and Find the tension in the cord. SEE ABOVE
*February 18, 2007*

**Physics/Math**

At time t1 = 2.00 s, the acceleration of a particle in counterclockwise circular motion is (9.00i + 8.00j) m/s^2. It moves at constant speed. At time t2 = 3.00s (3/4 of a revolution later), it's acceleration is (8.00i - 9.00j) m/s^2. Find the radius of the path taken by ...
*February 18, 2007*

**Physics/Math**

What are the x and y components of a vector a in the xy plane if it's direction is 215 degrees counterclockwise from the positive direction of the x axis and its magnitude is 12.9 m ? you would be in the third quadrant, so both x and y are negative. The values would have ...
*February 18, 2007*

**Physics/Math**

Given two vectors, a and b, such that a + b = a - b, find the magnitude of b. Consider the equation a + b = a - b to be n vector notation and both a and b have components. Subtract the a vector from both sides. You are left with b = -b That can only be true if b = 0. That ...
*February 18, 2007*

**Physics/Math**

A bicyclist travels in a circle of radius 35.0 m at a constant speed of 7.00 m/s. The bicycle-rider mass is 72.0 kg. Calculate the magnitude of the force of friction on the bicycle from the road. Calculate the magnitude of the net force on the bicycle from the road. I figured ...
*February 12, 2007*

**Physics/Math**

A certain string can withstand a maximum tension of 43 N without breaking. A child ties a 0.37 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks. Where is the stone on its...
*February 12, 2007*

**Physics/Math**

A stuntman drives a car (without negative lift) over the top of a hill, the cross section of which can be approximated by a circle of radius R = 110 m. What is the greatest speed at which he can drive without the car leaving the road at the top of the hill? I don't get it...
*February 12, 2007*

**Physics/Math**

A stuntman drives a car (without negative lift) over the top of a hill, the cross section of which can be approximated by a circle of radius R = 110 m. What is the greatest speed at which he can drive without the car leaving the road at the top of the hill?
*February 12, 2007*

**Physics/Math**

A certain string can withstand a maximum tension of 43 N without breaking. A child ties a 0.37 kg stone to one end and, holding the other end, whirls the stone in a vertical circle of radius 0.91 m, slowly increasing the speed until the string breaks. Where is the stone on its...
*February 12, 2007*

**Physics/Math**

A bicyclist travels in a circle of radius 35.0 m at a constant speed of 7.00 m/s. The bicycle-rider mass is 72.0 kg. Calculate the magnitude of the force of friction on the bicycle from the road. Calculate the magnitude of the net force on the bicycle from the road.
*February 12, 2007*

**Re: Physics/Math**

Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km...
*February 10, 2007*

**Re: Physics/Math**

A 3.0 kg block, initially in motion, is pushed along a horizontal floor by a force F of magnitude 18 N at an angle = 45° with the horizontal. The coefficient of kinetic friction between the block and floor is 0.25. (Assume the positive direction is to the right.) Calculate...
*February 10, 2007*

**Re: Physics/Math**

A 17 N horizontal force F pushes a block weighing 6.0 N against a vertical wall. The coefficient of static friction between the wall and the block is 0.68, and the coefficient of kinetic friction is 0.48. Assume that the block is not moving initially. Will the block move? In ...
*February 10, 2007*

**Physics/Math**

A 17 N horizontal force F pushes a block weighing 6.0 N against a vertical wall. The coefficient of static friction between the wall and the block is 0.68, and the coefficient of kinetic friction is 0.48. Assume that the block is not moving initially. Will the block move? In ...
*February 10, 2007*

**Physics/Math**

A 3.0 kg block, initially in motion, is pushed along a horizontal floor by a force F of magnitude 18 N at an angle = 45° with the horizontal. The coefficient of kinetic friction between the block and floor is 0.25. (Assume the positive direction is to the right.) Calculate...
*February 10, 2007*

**Physics/Math**

Calculate the ratio of the drag force on a passenger jet flying with a speed of 750 km/h at an altitude of 10 km to the drag force on a prop-driven transport flying at one-fifth the speed and half the altitude of the jet. At 10 km the density of air is 0.38 kg/m3 and at 5.0 km...
*February 10, 2007*

**Physics/Math**

In a pickup game of dorm shuffleboard, students crazed by final exams use a broom to propel a calculus book along the dorm hallway. If the 3.6 kg book is pushed from rest through a distance of 0.90 m by the horizontal 22 N force from the broom and then has a speed of 1.60 m/s...
*February 10, 2007*

**Physics.. last one.**

Four balls are suspended by cords. The longer, top cord loops over a frictionless pulley and pulls with a force of magnitude 95 N on the wall to which it is attached. The tensions in the shorter cords are T1 = 56.0 N (between ball A & B), T2 = 46.7 N (between ball B & C), and ...
*February 6, 2007*

**Physics .. help!!**

Imagine a landing craft approaching the surface of Callisto, one of Jupiter's moons. If the engine provides an upward force (thrust) of 3270 N, the craft descends at constant speed; if the engine provides only 2190 N, the craft accelerates downward at 40 m/s2. What is the...
*February 6, 2007*

**Physics - bobpursley**

Imagine a landing craft approaching the surface of Callisto, one of Jupiter's moons. If the engine provides an upward force (thrust) of 3270 N, the craft descends at constant speed; if the engine provides only 2190 N, the craft accelerates downward at 40 m/s2. What is the ...
*February 6, 2007*

**Physics**

Four balls are suspended by cords. The longer, top cord loops over a frictionless pulley and pulls with a force of magnitude 95 N on the wall to which it is attached. The tensions in the shorter cords are T1 = 56.0 N (between ball A & B), T2 = 46.7 N (between ball B & C), and ...
*February 6, 2007*

**Physics**

magine a landing craft approaching the surface of Callisto, one of Jupiter's moons. If the engine provides an upward force (thrust) of 3270 N, the craft descends at constant speed; if the engine provides only 2190 N, the craft accelerates downward at 40 m/s2. What is the ...
*February 3, 2007*

**Physics**

A worker drags a crate across a factory floor by pulling on a rope tied to the crate. The worker exerts a force of 450 N on the rope, which is inclined at 38° to the horizontal, and the floor exerts a horizontal force of 125 N that opposes the motion. Calculate the ...
*February 3, 2007*

**Physics**

Two horizontal forces act on a 2.4 kg chopping block that can slide over a frictionless kitchen counter, which lies in an xy plane. One force is F1 = (3.4 N) i + (3.7 N) j. Find the acceleration of the chopping block in unit-vector notation for each of the following second ...
*February 3, 2007*