By
vector addition.
In fact, velocity is a vector, with a magnitude intensity, a direction and a verse, so we can't simply do an algebraic sum of the two (or more velocities).
First we need to decompose each velocity on both x- and y-axis (if we are on a 2D-plane), then we should do the algebraic sum of all the components on the x- axis and of all the components on the y-axis, to find the resultants on x- and y-axis. And finally, the magnitude of the resultant will be given by

where Rx and Rx are the resultants on x- and y-axis. The direction of the resultant will be given by

where

is its direction with respect to the x-axis.
Resistance = (voltage) / (current) =
(120 V) / (0.5 A) = <em>240 ohms</em>
Answer:
y = 10.44cos(2t - 0.291) cm
Explanation:
y = Acos(2πt/T + φ) = Acos(2πt/π + φ) = Acos(2t + φ)
v = y' = -2Αsin(2t + φ)
10 = Acos(2(0) + φ) = Acosφ
6 = -2Αsin(2(0) + φ) = -2Asinφ
6/10 = -2Asinφ/Acosφ = -2tanφ
tanφ = -0.3
φ = -0.291 radians
10 = Acos(-0.291)
A = 10/cos(-0.291) = 10.44
Assuming that reaching a height 0 doesn’t stop the ball, and that it accelerates at 9.8 m/s^2, the ball would be traveling at 0.5 + 0.7*9.8 = 7.36 m/s downwards.