Three forces involved in brushing your teeth are first push, then pull, then push.
Before a person walks through burning coal, the person will make sure their feet are very wet. When they start walking on the coal, this moisture will evaporate and form a protective gas layer underneath the person's feet. You can see examples of this if you happen to drip some water on a hot stove or any very hot surface. The water will very easily glide around on top of a newly formed layer of air underneath it -- like air hockey pucks on an air hockey table. Note that when someone walks through burning coal, typically this is also done very quickly to prevent a great deal of exposure to possible harm. By walking quickly, thinking positively, and letting the water cushion you from immediate danger over a short distance, such a task is possible. You may have also heard of physics teachers demonstrating how this principle works by sticking their hand first in a bucket of water and then quickly in a bucket of boiling molten lead. In the lead, their hand is protected briefly by a layer of gas from the evaporated water (the water vapor). I'm fairly sure that there is a name for this particular layer of gas, but I'm afraid the name is beyond me at the moment. In other words, water vapor has a low heat capacity and poor thermal conduction. Very often, the coals or wood embers that are used in fire walking also have a low heat capacity. Sweat produced on the bottom of people's feet also helps form a protective water vapor. All of this together makes it possible, if moving quickly enough, to walk across hot coals without getting burned. WARNING: Do not attempt to perform any of the actions described above. You can seriously injure yourself. Answered by: Ted Pavlic, Electrical Engineering Undergrad Student, Ohio St. (citing my source)
Answer:
Answer:
4 ms
Explanation:
initial velocity, u = 75 m/s
final velocity, v = 0
distance, s = 15 cm = 0.15 m
Let the acceleration is a and the time taken is t.
Use third equation of motion
v² = u² + 2 a s
0 = 75 x 75 - 2 a x 0.15
a = - 18750 m/s^2
Use first equation of motion
v = u + at
0 = 75 - 18750 x t
t = 4 x 10^-3 s
t = 4 ms
thus, the time taken is 4 ms.
Explanation:
Answer:
answer will be c: 1.5 seconds :)
Answer:
The current through the inductor at the end of 2.60s is 9.7 mA.
Explanation:
Given;
emf of the inductor, V = 41.0 mV
inductance of the inductor, L = 13 H
initial current in the inductor, I₀ = 1.5 mA
change in time, Δt = 2.6 s
The emf of the inductor is given by;
Therefore, the current through the inductor at the end of 2.60 s is 9.7 mA.
