Penjelasan:

1. m = 3 kg, g = 10 m/s², h = 20 m

Jawab :

Ep = m . g . h

Ep = 3 . 10 . 20

Ep = 600 J

2. m = 500 kg, Ep = 490000 J, g = 10 m/s²

Jawab :

Ep = m . g . h

490000 = 500 . 10 . h

490 = 5 . h

h = 98 meter

3. h = 5 m, Ep = 39,2 J

Massa mangga tersebut = ____?

Jawab :

Ep = m . g . h

39,2 = m . 10 . 5

39,2 = m . 50

m = 0,784 kg atau 784 gram

4. m = 2000 kg , v = 100 km/jam

Energi kinetiknya = ____?

Jawab :

100 km/jam → ²⁵⁰/₉ m/s

Ek = ¹/₂ . m . v²

Ek = ¹/₂ . 2000 . ²⁵⁰/₉

Ek ≈ 27777,78 J

5. v₀ = 0 m/s

Ek = 1,6 J

a = 4 m/s²

t = 1 detik

Massa benda itu = ___?

Jawab :

Kecepatan akhir benda :

vt = v₀ + a . t

vt = 0 + 4 . 1

vt = 4 m/s

Massa benda itu :

Ek = ¹/₂ . m . v²

1,6 = ¹/₂ . m . 4²

1,6 = 8 . m

m = 0,2 kg atau 200 gram