Answer:
Explanation:
Given
coefficient of kinetic friction
=0.34
inclination 
weight of block=51 N
(a) When block is moving upward friction force acts downward
thus

as block is moving with constant velocity thus
is zero



(b)When Block slides down the wall friction changes its direction to oppose the block




The ration of output work to input work expressed as a percentage is called <u>Efficiency</u>.
Lighting gives a sense of scale (The sky)
Answer:
Explanation: is that suppose to be the question or are you just saying?
Group 0 - they are called the NOBLE GASES
(as they're very unreactive) because...
ALL of their atoms are full.
Example : Helium contains 2 electrons so it's outer shell is full