Answer: 3217.79 hours.
Explanation:
Given, A 140 lb. climber saved her potential energy as she descended from Mt. Everest (Elev. 29,029 ft) to Kathmandu (Elev. 4,600 ft).
Power = 0.4 watt
Mass of climber = 140 lb
= 140 x 0.4535 kg [∵ 1 lb= 0.4535 kg]
⇒ Mass of climber (m) = 63.50 kg
Let
and 
Now, Energy saved =
![\text{Power}=\dfrac{\text{energy}}{\text{time}}\\\\\Rightarrow 0.4=\dfrac{4633620.91}{\text{time}}\\\\\Rightarrow\ \text{time}=\dfrac{4633620.91}{0.4}\approx11584052.28\text{ seconds}\\\\=\dfrac{11584052.28}{3600}\text{ hours}\ \ \ [\text{1 hour = 3600 seconds}]\\\\=3217.79\text{ hours}](https://tex.z-dn.net/?f=%5Ctext%7BPower%7D%3D%5Cdfrac%7B%5Ctext%7Benergy%7D%7D%7B%5Ctext%7Btime%7D%7D%5C%5C%5C%5C%5CRightarrow%200.4%3D%5Cdfrac%7B4633620.91%7D%7B%5Ctext%7Btime%7D%7D%5C%5C%5C%5C%5CRightarrow%5C%20%5Ctext%7Btime%7D%3D%5Cdfrac%7B4633620.91%7D%7B0.4%7D%5Capprox11584052.28%5Ctext%7B%20seconds%7D%5C%5C%5C%5C%3D%5Cdfrac%7B11584052.28%7D%7B3600%7D%5Ctext%7B%20hours%7D%5C%20%5C%20%5C%20%5B%5Ctext%7B1%20hour%20%3D%203600%20seconds%7D%5D%5C%5C%5C%5C%3D3217.79%5Ctext%7B%20hours%7D)
Hence, she can power her 0.4 watt flashlight for 3217.79 hours.
Answer:
1)
Force on bar magnet = 0
Torque on bar magnet = 0
2)
Force on bar magnet = 0
Torque on bar magnet = 0.177 Nm
3)
Force on bar magnet = 0
Torque on bar magnet = 0.25 Nm
Explanation:
Part 1)
net force on bar magnet in uniform magnetic field is always zero
Torque on bar magnet is given as

when bar magnet is inclined along z axis along magnetic field
then we will have

Part 2)
net force on bar magnet in uniform magnetic field is always zero
Torque on bar magnet is given as

when bar magnet is pointing 45 degree with z axis then we will have



Part 3)
net force on bar magnet in uniform magnetic field is always zero
Torque on bar magnet is given as

when bar magnet is pointing 90 degree with z axis then we will have



Answer:
a) 5.197rev/s
b) Kf/Ki =2.28
Explanation:
a) Angular momentum of the system L = Iw
ButLi=Lf
Kiwi =Ifwf
wf = (Ii/If)will = (4.65/3.4)×3.8=5.197rev/s
b)Kinetic energy KE= 0.5Iw^2
Ki = 0.5Iiwi^2
Kf=0.5Ifwf^2
Kf/Ki = Ifwf/Iiwi
Kf/Ki = (4.65/3.4))(5.197/3.8)
Kf/Ki = 1.22(1.368)^2
Kf/Ki = 2.28
Since the baseball is half the weight of the softball, the baseball has to go twice as fast as the softball.
So the best answer would be D