Billiard ball A, mass 0.17 kg, is moving due east with a velocity of 4.0 m/s. It strikes stationary billiard ball B, which has the
same mass. After the collision, ball A moves at an angle of 30°
north of east with a velocity of 3.5 m/s. Ball B moves at an
angle of 60° south of east. What is the speed of ball B?

an obstruction

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

it would be kevlar ^^

at right angles to each other