Question 7 of 10 A student is transmitting sound waves through various materials. Through
which metal in the table will the sound waves travel the fastest?
Aluminum
Copper
Lead
Brass
(70% Cu,
30% Zn)
6,420
4,700
5,010
1,960
Speed of
sound
(m/s)
A. Copper
B. Brass
Ο Ο Ο Ο
C. Aluminum
O D. Lead

Ray 2 should cross through the focal point on the right side of the lens

Distance covered, s = 8ft - 4ft = 4 ftinitial velocity, u = 34 ft/sthe acrobat is moving upwards and therefore, a = -g = -9.81 m/s^2 = 32.19 ft/s^2applying equation of motion; s = ut -1/2gt^2then,4 = 34t -1/2*32.19t^24 = 34t - 16.095t^2rearranging; -16.095t^2 + 34t - 4 = 0solving the quadratic equation; t = {-34 +/- sqrt [34^2 - 4(-16.)]}/2(-16.095) = 1.06 +/- 0.93 = 0.13 or 1.99the acrobat will take 0.13 seconds to be at 8 ft above the ground. additionally, once at the maximum height, the acrobat will move down and be at the same spot (that is height) after 1.99 seconds moving down.