Than to lift it straight up.
ROPE CLIMBING (2011;3 - AS90940)
A girl of mass 60 kg uses 5 100 J of energy when she climbs a vertical rope.
(a)
Calculate the maximum height it would be possible for the girl to reach.
(b)
In reality, the girl reaches a height of only 8 m.
Explain why the energy used by the girl during the climb does not equal the
work she does to reach the vertical height of 8 m.
In your answer you should:
name the type of energy the girl has when she is 8 m above the ground
calculate the work done to reach a height of 8 m above the ground
calculate the difference between the work done and the energy used by the
girl
•
explain where the "missing" energy has gone, and why this occurs.

Explanation:

(a) PE = mgh

5100 J = (60 kg) (10 m/s²) h

h = 8.5 m

(b) At 8 m, the girl has a gravitational potential energy of:

PE = mgh

PE = (60 kg) (10 m/s²) (8 m)

PE = 4800 J

The difference in energy is 300 J.  This energy is converted into heat in the girl's muscles.

can be answered using momentum.

momentum = p

p1= mass1 * velocity1

p1 = p2

therefore

p1 = 6kg * 4m/s

p1 = 24kgm/s

p2=m2 * v2

24 kgm/s = 7kg * v2

v2 = 24 kgm/s / 7kg

v2= 3.42 m/s

report!

explanation:

physics means: "the branch of science concerned with the nature and properties of matter and energy. the subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms."