the answer is A. The aluminum has 0.84 ohms more resistance.
Explanation:
At the instant of release there is no force but an acceleration of a, this means the ball is falling freely under the force of gravity. Then the acceleration would be due to force of gravity and acceleration a = g =9.81 m/s^2.
g= acceleration due to gravity
Answer:
1/2 M V^2 = .1 M g H where 10% of PE goes into KE
V^2 = .2 g H = .2 * 9.8 * (2100 - 1600) = 980 m^2 / s^2
V = 31.1 m/s increase in speed during descent
1 km / hr = 1000 m / 3600 sec = .278 m/s
V = 31.1 m/s / (.278 m/s / km /hr)= 112 km/hr