Question

How much potential energy does a 40 kg rock have if it was on a 10m cliff?

How much potential energy does the same 40 kg rock have if it was on a 5 m cliff?

Answer 1

Answer:4000 for the first one, for the second one it is 2000

Explanation:

Mass=40kg

Height=10m

Gravity=10Nkg.(always taken)

Thus,

40×10×10

=4000

Mass=40kg

Height=5m

Gravity=10Nkg.(again, it is always taken)

Thus,

40 x 5 x 10

=2000

Answer 2

P.E = mgh

• m = mass
• g = acceleration due to gravity = 9.8 m/s²
• h = height

For 10m cliff

• m = 40 kg
• g = 9.8 m/s²
• h = 10 m

Now,

P.E. = mgh

P.E. = 40 × 9.8 × 10

P.E = 3920 Joule

For 5m cliff

• m = 40 kg
• g = 9.8 m/s²
• h = 5 m

Now,

P.E. = mgh

P.E. = 40 × 9.8 × 5

P.E = 1960 Joule