Answer:
(a) Current flowing through truck battery is 180 A
(b) Time taken in calculator is 333.33 s
Explanation:
(a) Given:
The charge on the truck battery,q = 720 C
Time, t = 4.00 s
Consider I be the current flowing through truck battery.
The relation between current, charge and time is:
I = q/t
Substitute the suitable values in the above equation.
I = 180 A
(b) Given:
The charge on the calculator,q = 7.00 C
The current flowing through calculator, I = 0.3 mA = 0.3 x 10⁻³ A
Consider t be the time.
The relation between current, charge and time is:
t = q/I
Substitute the suitable values in the above equation.
I = 333.33 s
Apply conservation of angular momentum:
L = Iw = const.
L = angular momentum, I = moment of inertia, w = angular velocity, L must stay constant.
L must stay the same before and after the professor brings the dumbbells closer to himself.
His initial angular velocity is 2π radians divided by 2.0 seconds, or π rad/s. His initial moment of inertia is 3.0kg•m^2
His final moment of inertia is 2.2kg•m^2.
Calculate the initial angular velocity:
L = 3.0π
Final angular velocity:
L = 2.2w
Set the initial and final angular momentum equal to each other and solve for the final angular velocity w:
3.0π = 2.2w
w = 1.4π rad/s
The rotational energy is given by:
KE = 0.5Iw^2
Initial rotational energy:
KE = 0.5(3.0)(π)^2 = 14.8J
Final rotational energy:
KE = 0.5(2.2)(1.4)^2 = 21.3J
There is an increase in rotational energy. Where did this energy come from? It came from changing the moment of inertia. The professor had to exert a radially inward force to pull in the dumbbells, doing work that increases his rotational energy.
Alright. If it’s running at a constant speed of 120 km/h, in one hour it will have traveled 120 kilometers. hence “kilometers per hour”
20 minutes is 1/3 of an hour so 120/3 will be 40
therefore, in 20 minutes the cheetah would’ve ran 40km if it maintained 120km/h for 20 minutes.
The wavelengths of terrestrial radiation from earth's surface are concentrated in thermal infrared spectrum.
<u>Explanation:</u>
The wavelengths used in thermal infrared are in the range of micrometer ranging from 8 to 15. Terrestrial radiation is defined as the radiation that is originating from earth due to radioactive materials like uranium, thorium e.t.c.
Increase in terrestrial radiation by the use of radioactive materials will consequently increase global warming as it releases green house gases thereby degrading the quality of earth's atmosphere.
