6. a copper penny has a mass of 3.1 g and a volume of 0.35 cm3. what is the density of copper?

What if? physicists often measure the momentum of subatomic particles moving near the speed of light in units of mev/c, where c is the speed of light, and 1 mev = 1.6 ✕ 10−13 kg · m2/s2. based on this, what are the units of momentum for a high-speed subatomic particle in terms of fundamental si units?

Karen is running forward at a speed of 9 m/s. she tosses her sweaty headband backward at a speed of 20 m/s. the speed of the headband, to the nearest whole number relative to a stationary observer watching karen

First to answer will be the brainliest i need the answer asap