Show that the expressions (ds)2 (c dt)2- (dx)2 - (dy) - (dz)2 is invariant (i. e, a scalar quantity) under lorentz transformations. this is the "four-dimensional distance" between events and is also known as the metric. show that if (ds)2 < 0 the two events cannot be causally connected, i. e., there cannot not be any information transmitted from one to the other even at light speed

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

the old price per ounce is c/4.

the new price per ounce is c/3.6.

the ratio of the old price to the new one is

(c/4)/(c/3.6) = (c/c)×(3.6/4) = 0.9 . . = 9/10 . . "nine tenths" in either form

answer a fan shaped mass of sediment deposited at the base of a mountain front do to an abrupt change in stream gradient;