The first one is D
The second one is true
At start: PE only
At end: KE and energy lost to friction
PE = KE + E
E = PE - KE
= mgh - (1/2)mv^2
= (40)(9.8)(12) - (.5)(40)(10)^2
= 2704J
Step-by-step explanation:
(0,0) (1,45) (2,90) (3, 135) (4, 180) etc, etc
7^2 I think is the write answer
