Answer:
(a) 19.25 N-m
(b) 25.67 N-m
(c) 0 N-m
Explanation:
Given:
Length of the pedal arm (L) = 0.177 m
Downward force 
= 145 N
Magnitude of torque is given by the formula:
Where, 
(a)
Given:
°
Therefore, torque is given as:
Therefore, the torque is 19.25 N-m.
(b)
Given:
°
Therefore, torque is given as:
Therefore, the torque is 25.67 N-m.
(c)
Given:
°
Therefore, torque is given as:
Therefore, the torque is 0 N-m.
The correct answer is: Option (D) length, speed
Explanation:
According to Faraday's Law of Induction:
ξ = Blv
Where,
ξ = Emf Induced
B = Magnetic Induction
l = Length of the conductor
v = Speed of the conductor.
As you can see that ξ (Emf/voltage induction) is directly proportional to the length and the speed of the conductor. Therefore, the correct answer will be Option (D) Length, Speed
Answer:
the mass of water is 0.3 Kg
Explanation:
since the container is well-insulated, the heat released by the copper is absorbed by the water , therefore:
Q water + Q copper = Q surroundings =0 (insulated)
Q water = - Q copper
since Q = m * c * ( T eq - Ti ) , where m = mass, c = specific heat, T eq = equilibrium temperature and Ti = initial temperature
and denoting w as water and co as copper :
m w * c w * (T eq - Tiw) = - m co * c co * (T eq - Ti co) = m co * c co * (T co - Ti eq)
m w = m co * c co * (T co - Ti eq) / [ c w * (T eq - Tiw) ]
We take the specific heat of water as c= 1 cal/g °C = 4.186 J/g °C . Also the specific heat of copper can be found in tables → at 25°C c co = 0.385 J/g°C
if we assume that both specific heats do not change during the process (or the change is insignificant)
m w = m co * c co * (T eq - Ti co) / [ c w * (T eq - Tiw) ]
m w= 1.80 kg * 0.385 J/g°C ( 150°C - 70°C) /( 4.186 J/g°C ( 70°C- 27°C))
m w= 0.3 kg
It is gonna be C 0.37 and 19.1
