A motor spins upward the flywheel with a persistent torque
of 50N⋅m.
What time does it take the flywheel to get to the top speed?
From the equation:
Tj = J*dω/dt
you can get the two equations:
Δt1= J1*Δω/Tj = 240*125.66/50 = 603.17 sec
Δt2= J2*Δω/Tj = 120*125.66/50 = 301.58 sec
is the magnitude of the magnetic field made by the current
<u>Explanation:</u>
Given data:

Magnetic field of earth, 
We need to find the magnetic field of wire, 
The compass needle moves toward a direction of magnetic field. The current in wire makes a magnetic field in available space where the compass is on the ground. The vector sum of the Earth's magnetic field and the wire's magnetic field represents the net magnetic field, as shown in the attached drawing, expressing the angle:

By substituting the given values, we get


Yeah i think with a car or a plane:)
Step 1: Find the upward acceleration.
d = 107 m
a = ???
vi = 0
t = 14.4 sec
d = vi * t + 1/2 at^2
107 = 1/2 a * 14.4^2
a = 214 / (14.4)^2
a = 1.03 m/s^2
Step 2: Find the Volume of the balloon and from that the mass.
V = 4/3 * pi * r^3
r = 6.52 m
V = 4/3 x pi x 6.52^3
V= 1,161 m^3.
Density of air = m/V 1.29 = m/ 1161
M = 1.29 x 1161
m = 1498 kg
Step 3: The force keeping this in equilibrium = F = m* g
F = 1498 * 9.81 = 14692 N
Step 4: Find the mass needed to cause the upward acceleration.
14692 = (1498 - x) * (9.81 + 1.03)
14692 = (1498 - x) * 10.84 Divide both sides by 10.84
1355.35 = 1022 - x
1355.35 - 1022
x = 333.35 kg