Nomor 4, 5, dan 7 tolong yg bisa dgn caranyaaaaaa

4)
Qtotal = Q perub.suhu + Q menguap
Qtotal = m . c air . DeltaT + m . U
Qtotal = m (c air . DeltaT + U)
Qtotal = 4 (4200.(100-75) + 2.260.000)
Qtotal = 4 (105000 + 2.260.000)
Qtotal = 9.460.000 joule
Qtotal = 9460 kJ

Jawaban A


5)
dik:
t = 2 s
s = 5 meter
vo = 0

cari a
s = vo.t +1/2.a.t^2
5 = 0 + 1/2.a.2^2
5 = 2a
a = 2,5 m/s^2

saat t = 4 sekon
s = vo.t + 1/2.a.t^2
s = 0 + 1/2. 2,5. 4^2
s = 20 meter
jawaban D

7)
dik:
h1 = 10 m
v1 = 0 (jatuh bebas) EK1 =0
m = 0,3 kg
dit : EK pd h2 = 7 m

jawab:
pakai hukum kekekalan energi mekanik
EM1 = EM2
EK1 + EP1 = EK2 + EP2
0 + mgh1 = EK2 + mgh2
EK2 = m.g(h1 -h2)
EK2 = 0,3 . 10 .(10-7)
EK2 = 9 J

jawaban C