If we assume that Earth is a solid sphere, then I = (2/5)mr² = (2/5) * 5.98e24kg * (6.371e6m)² = 9.71e37 kg·m²
torque τ = Iα, but also τ = F*r = 3.98e7N * 6.371e6m = 2.54e14 N·m Since τ = τ, 2.54e14 N·m = 9.17e37kg·m² * α α = 3.61e-23 rad/s²
ωo = 2πrads / (24h*3600s/h) = 7.27e-5 rad/s ω1 = 2πrads / (28h*3600s/h) = 6.23e-5 rad/s
Plug in numbers t = 2/5 * (5.98 * 10^24 kg) * (6.37*10^6 m) * (7.27 * 10^-5 rad/s - 6.23 * 10^-5 rad/s) / (3.98*10^7 N) = 3.98*10^22 s = 1.26*10^17 yrs
Answer:
(A) 6174J, 0J.
(B) 7374J
(C) 7374J
Explanation:
See the attachment below for the calculation.
The princi6of conservation of energy has been used.
E = K1 + U1 = K2 + U2
Where E = total mechanical energy.
Taking the bottom as reference, and h =0 and as a result U2 = mg(0) = 0J.
The complete solution to the problem can be found in the attachment below.
Answer:
4) moves with constant velocity
Explanation:
If an object is in motion, three things can happen:
1. The object slows down in speed.
This means a net force is needed to be able to slow the object down in speed.
2. The object increases in speed.
This means a net force is needed to be able to increase the speed of the object.
3. The object remains in motion at the same speed.
No net zero unbalanced force is needed.
This is the given situation. So this is the right answer.
Answer: 3.21 N
For weight, we will multiply by 
Hence, the rock would weigh 3.21 N.
Given Information:
Magnetic field = B = 1×10⁻³ T
Frequency = f = 72.5 Hz
Diameter of cell = d = 7.60 µm = 7.60×10⁻⁶ m
Required Information:
Maximum Emf = ?
Answer:
Maximum Emf = 20.66×10⁻¹² volts
Explanation:
The maximum emf generated around the perimeter of a cell in a field is given by
Emf = BAωcos(ωt)
Where A is the area, B is the magnetic field and ω is frequency in rad/sec
For maximum emf cos(ωt) = 1
Emf = BAω
Area is given by
A = πr²
A = π(d/2)²
A = π(7.60×10⁻⁶/2)²
A = 45.36×10⁻¹² m²
We know that,
ω = 2πf
ω = 2π(72.5)
ω = 455.53 rad/sec
Finally, the emf is,
Emf = BAω
Emf = 1×10⁻³*45.36×10⁻¹²*455.53
Emf = 20.66×10⁻¹² volts
Therefore, the maximum emf generated around the perimeter of the cell is 20.66×10⁻¹² volts
