Answer:
fcosθ + Fbcosθ =Wtanθ
Explanation:
Consider the diagram shown in attachment
fx= fcosθ (fx: component of friction force in x-direction ; f: frictional force)
Fbx= Fbcosθ ( Fbx: component of braking force in x-direction ; Fb: braking force)
Wx= Wtanθ (Wx: component of weight in x-direction ; W: Weight of semi)
sum of x-direction forces = 0
fx+ Fbx=Wx
fcosθ + Fbcosθ =Wtanθ
Answer: (1) The resistance increases and the current decreases.
Explanation:
When the temperature of the filament increases, the vibrational energy of the constituent atoms increases which leads to increase in inter-atomic collision. Thus, the resistance would increase. The increases in resistance would obstruct the flow of charges more leading to decrease in the value of the current.
Hence, when the temperature of the filament increase, the resistance increases and current decreases.
Efficiency. The ratio of energy which was transferred to a useful form compared to the total energy initially supplied is called the efficiency of the device. Efficiencies can be written as decimals like 0.33 or percentages 33%. To convert a efficiency expressed as a decimal to a percentage you need to multiply by 100.
Answer:

Explanation:
(a) Free-body diagram attached.
(b) The stone attached with the string experiences both centripetal (towards the center) and centrifugal (away from the center) forces. The tension of the string counters the centrifugal force until it breaks.
We know that,
Centrifugal force = 
where,
= mass of the stone
= velocity of the stone
= length of the string
To find the maximum speed attained by the stone without the string breaking, we must equate:

or, 