The half life of .t meson at rest is 2.5 × 10-8 second. a beam of π+ mesons is generated at a point 15 meters from a detector. only ½ of the π+mesons live to reach the detector. find the speed of the t mesons, specifying whether you have used time dilation or length contraction

Agraduated cylinder contains 63.0 ml of water. a piece of gold, which has a density of 19.3 g/ cm3, is added to the water and the volume goes up to 64.5 ml. calculate the mass in grams of the gold that was added to the water. explain how you got your answer.

Talia is manufacturing rolls of wire for hanging pictures. she needs a material that is so that it can easily be pulled into wire without breaking.

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?