Explanation:
The test for hydrogen consists of holding a burning splint held at the open end of a test tube of gas. If the gas is hydrogen it burns with a loud “squeaky pop” which is the result of the rapid combustion of hydrogen with oxygen to produce water.
Potential energy = (mass) · (gravity) · (height)
PE = (60 kg) · (9.8 m/s²) · (10 m)
PE = (60 · 9.8 · 10) · (kg · m²/s² )
PE = 5,880 joules
Explanation:
Given that,
Mass of the rock climber, m = 90 kg
Original length of the rock, L = 16 m
Diameter of the rope, d = 7.8 mm
Stretched length of the rope, 
(a) The change in length per unit original length is called strain. So,

(b) The force acting per unit area is called stress.

(c) The ratio of stress to the strain is called Young's modulus. So,

Hence, this is the required solution.
Friction would inhibit your speed and maximum work potential so, friction is the answer.
Hope this helps, Brainliest please.