Copper has an atomic radius of 0.128nm an fcc crtstak structure. the atomic weight of copper is 63.5g/mol. compute its theoretical density. (in the literature, the measured density of copper is found as 8: 98g/cm^3 first decide the type of the conventional unit cell and evaluate its volume. then evaluate how many cu atoms contain in the conventional cell)

the word that best describes martin luther king jr.'s tone in the video is dignified

martin luther king, jr. was a social activist and baptist minister who played a key role in the american civil rights movement from the mid-1950s until his assassination in 1968. the video shows his manner and attitude having or showing a composed or serious manner that is worthy of respect so dignified is the correct answer

what is the speed of a softball that travels 20m in 2secs

speed = 20/2 = 10 m/s

note: the given question is incomplete.

complete question is given below.

which is an example of kinetic energy?

a. the energy stored in ethanol  

b. a hockey puck sliding across the ice  

c. a compressed spring  

d. a ball sitting at the top of a ramp

solution: the kinetic energy is the energy posses by the virtue of the motion of the object.

in the given options, a, c and d are the example of potential energy because it is the energy posses by the virtue of the rest of the object. but option b has the kinetic energy as the object is in motion.

hence, a hockey puck sliding across the ice   is the apex example of kinetic energy.

so, the option (b) a hockey puck sliding across the ice   is the correct option.

conservation of mass

mass before something happens = mass afterwards