If the mass of an object is measured to be 53.5 ± 0.1 g and its volume is measured to be 22.30 ± 0.05 cm^3 , what is the density? report the density uncertainty in both forms: as a percentage and as an absolute number with units.

What is the force that opposes motion and works against the downward pull? a) friction b) gravity c) weight d) acceleration

Matter that emits no light at any wavelength is called

You have been hired to design a spring-launched roller coaster thatwill carry two passengers per car. the car goes up a 10-m highhill, then descends 15m to the track's lowest point. you'vedetermined that the spring can be compressed a maximum o 2.0m andthat a loaded car will have a maximum mass of 400kg. for safetyreasons, the spring constant should be 10% larger than the minimumneeded for the car to just make it over the top. a) what spring constant (k) should you specify ? b) what is the maximum speed of a 350 kg car if the spring iscompressed the full amount.