We will model the arm of a person curling 20 kg as a bar of…
We will model the arm of a person curling 20 kg as a bar of length 37 cm with a weight on the end. The bicep attaches to the bar 7cm from the axis of rotation of the bar, and the other end of the bicep is attached 26 cm from the axis of rotation to the upper arm, as drawn below. What is the tension in the bicep if the weight is in static equilibrium? question8.png
Read DetailsA cube with a side of length 2 m is suspended at a depth of…
A cube with a side of length 2 m is suspended at a depth of 1000 m inside the ocean. Its top and bottom sides are parallel with the surface of the water. What is the magnitude of difference in the force due to fluid pressure on the top of the cube and on the bottom of the cube? Take the density of the sea water to be 1025 kg/m3.
Read DetailsA 200-kg disk (I = 1/2 mR^2) with a radius of 3 m is spinnin…
A 200-kg disk (I = 1/2 mR^2) with a radius of 3 m is spinning with an angular velocity of w = 6 s-1. A person with a mass of 50 kg initially stands at a distance of 1 m from the axle of the spinning disk, and then walks to a position 2 m from the axle of the disk. Treat the person as a point mass (I = mR^2). What is the new angular velocity of the disk-person system?
Read DetailsA 40,000 kg truck is held up by 18 wheels. The air pressure…
A 40,000 kg truck is held up by 18 wheels. The air pressure inside of the tires is 60 psi = 4.13 X 105 Pa. Suppose that this is also the pressure that the tires exerts on the ground. What is the area of each tire which presses on the ground?
Read DetailsAn incompressible fluid flows into a circular cross-sectione…
An incompressible fluid flows into a circular cross-sectioned pipe with a diameter of d = 7 cm. The speed of the fluid is 10 m/s. The pipe changes diameter halfway along its length to a 10 cm diameter pipe. What is the speed of fluid flow in in this wider pipe?
Read DetailsA 3 mm diameter wire (with a circular cross section) which i…
A 3 mm diameter wire (with a circular cross section) which is 100 ft long when there is no force applied to it, stretches by 4 inches when a 8600 N tension force is applied to the wire. What is Young’s modulus for the material the wire is made of?
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