What type of composition does an igneous rock have that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals?

The type of composition that igneous rocks have that contains mostly plagioclase feldspar and about 30 percent dark silicate minerals would be andesitic. I am hoping that this answer has satisfied your query about and it will be able to help you.

initial speed when it is dropped is 150 ft/s

now at the same moment the acceleration due to gravity is perpendicular to its velocity

so as we know that

now we have centripetal acceleration a = 32 ft/s^2 as its perpendicular to velocity

while tangential acceleration at the same moment will be zero

so

now radius of curvature is given as

so the radius of curvature just after it is dropped is 703.125 ft