Answer:
The average power is calculated as 735.0 W
Solution:
As per the question:
Total mass, M = 1200 kg
Counter mass of the elevator, m = 950
Distance traveled by the elevator, d = 54 m
Time taken, t = 3 min = 180 s
Now,
To calculate the average power:
First, we find the force needed for lifting the weight:
Force, F = (M - m)g =
Now, the work done by this force:
W = Fd =
Average power is given as:
When silver is poured into the mould the it will solidify
In this process the phase of the Silver block will change from liquid to solid.
This phase change will lead to release in heat and this heat is known as latent heat of fusion.
The formula to find the latent heat of fusion is given as
here given that
now we can find the heat released
So it will release total heat of 55.5 kJ when it will solidify
Answer:
6.86 m/s
Explanation:
This problem can be solved by doing the total energy balance, i.e:
initial (KE + PE) = final (KE + PE). { KE = Kinetic Energy and PE = Potential Energy}
Since the rod comes to a halt at the topmost position, the KE final is 0. Therefore, all the KE initial is changed to PE, i.e, ΔKE = ΔPE.
Now, at the initial position (the rod hanging vertically down), the bottom-most end is given a velocity of v0. The initial angular velocity(ω) of the rod is given by ω = v/r , where v is the velocity of a particle on the rod and r is the distance of this particle from the axis.
Now, taking v = v0 and r = length of the rod(L), we get ω = v0/ 0.8 rad/s
The rotational KE of the rod is given by KE = 0.5Iω², where I is the moment of inertia of the rod about the axis of rotation and this is given by I = 1/3mL², where L is the length of the rod. Therefore, KE = 1/2ω²1/3mL² = 1/6ω²mL². Also, ω = v0/L, hence KE = 1/6m(v0)²
This KE is equal to the change in PE of the rod. Since the rod is uniform, the center of mass of the rod is at its center and is therefore at a distane of L/2 from the axis of rotation in the downward direction and at the final position, it is at a distance of L/2 in the upward direction. Hence ΔPE = mgL/2 + mgL/2 = mgL. (g = 9.8 m/s²)
Now, 1/6m(v0)² = mgL ⇒ v0 =
Hence, v0 = 6.86 m/s