A hydrometer is a device used to measure the density of a liquid. It is a cylindrical tube weighted at one end, so that it floats with the heavier end downward. The tube is contained inside a large "medicine dropper," into which the liquid is drawn using the squeeze bulb (see the drawing). For use with your car, marks are put on the tube so that the level at which it floats indicates whether the liquid is battery acid (more dense) or antifreeze (less dense). The hydrometer has a weight of W = 6.77 × 10-2 N and a cross-sectional area of A = 8.99 × 10-5 m2. How far from the bottom of the tube should the mark be put that denotes (a) battery acid (rho = 1280 kg/m3) and (b) antifreeze (rho = 1073 kg/m3)?

Air is held within a frictionless piston-cylinder container, which is oriented vertically. the mass of the piston is 0.45 kg and the cross-sectional area is 0.0030 m2. initially (state 1) the pressure of the gas is sufficient to support the weight of the piston as well as the force exerted by the atmospheric pressure ( 101.32 kpa). the volume occupied by the air within the cylinder in state 1 is 1.00 liter. one end of a spring (with spring constant k = 1000 n/m) is attached to the top of the piston, while the other end of the spring is attached to a stage that can move vertically. initially the spring is undeflected and therefore exerts no force. then the stage is then moved quasistatically downward a distance of 10.0 cm, at which point the system reaches state 2. the piston-cylinder is not insulated; rather it remains in diathermal contact with the surroundings, which are at a constant temperature of 300 k. what is the change of pressure within the container?

In positive numbers less than 1, the zeros between the decimal point and a non-zero number are blank significant

This is important. 1. which of the following is an si base unit for measuring length? (2 points) inch gram meter mole 2. which of the following units for distance is an si unit? (2 points) centimeter foot inch yard 3. which of the following tools should a scientist use to measure an object in meters? (2 points) electronic balance pan balance tape measure thermometer