Answer:
The temperature of the windings are 60.61 °C
Explanation:
Step 1: Data given
Resistance = 50 Ω
Temperature = 20.0 °C
After the motor has run for several hours the resistance rises to 58Ω.
Step 2: Calculate the new temperature
Formula: R = Rref(1 + α(T-Tref))
⇒with α = temperature coëfficiënt of Cupper at 20 °C = 0.00394/°C
⇒with Tref = reference temperature = 20°C
⇒with T = end temperature = TO BE DETERMINED
⇒with R = resistance at end temperature = 58Ω
⇒with Rref = resistance at reference temperature = 50 Ω
==> T = (R/Rref - 1)/α + Tref
T = (58/50) - 1 )/ 0.00394 + 20
T = 60.61 °C
The temperature of the windings are 60.61 °C
Answer:
A) False
B) False
C) True
D) True
E) True
Explanation:
A) The formula for tangential speed v in term of angular speed ω and radius of rotation r is
So if the angular speed is constant and 0, the tangential speed is also 0. A) is false
B) False because of the centripetal acceleration:
C) True because of the formula for tangential acceleration in term of angular acceleration α is
D) True because same as D), if it has angular acceleration, it would have a tangential acceleration. Also from B) the centripetal acceleration will come with time as soon as angular speed is generated by angular acceleration.
E) True and same explanation as from B)
here given that object is dropped from height h = 50 m
So here we can say
initial speed is ZERO
acceleration is due to gravity
now in order to find time to reach the ground we can use kinematics
now plug in all values in it
so it will take 3.2 s to reach the ground
Answer:
k1 + k2
Explanation:
Spring 1 has spring constant k1
Spring 2 has spring constant k2
After being applied by the same force, it is clearly mentioned that spring are extended by the same amount i.e. extension of spring 1 is equal to extension of spring 2.
x1 = x2
Since the force exerted to each spring might be different, let's assume F1 for spring 1 and F2 for spring 2. Hence the equations of spring constant for both springs are
k1 = F1/x -> F1 =k1*x
k2 = F2/x -> F2 =k2*x
While F = F1 + F2
Substitute equation of F1 and F2 into the equation of sum of forces
F = F1 + F2
F = k1*x + k2*x
= x(k1 + k2)
Note that this is applicable because both spring have the same extension of x (I repeat, EXTENTION, not length of the spring)
Considering the general equation of spring forces (Hooke's Law) F = kx,
The effective spring constant for the system is k1 + k2
