The answer is:
Forces acting on the sled are paired with equal and opposite forces.
The explanation:
About to push you, this means that he doesn't push yet. If the sled is on level ground and no one is pushing it, then forces are equal and opposite.
The gravity force pulls down and the ground pushes up.
This is Newton's third law:
Newton's third law: If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A.
This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.
We can also see Newton’s third law at work by taking a look at how people move about. Consider a swimmer pushing off from the side of a pool.
Answer:
The natural frequency = 50 rad/s = 7.96 Hz
Damping ratio = 0.5
Explanation:
The natural frequency is calculated in this manner
w = √(k/m)
k = spring constant = 5 N/m
m = mass = 2 g = 0.002 kg
w = √(5/0.002) = 50 rad/s
w = 2πf
50 = 2πf
f = 50/(2π) = 7.96 Hz
Damping ratio = c/[2√(mk)] = 0.1/(2 × √(5 × 0.002)) = 0.5
Answer:
There are four different stages of sleep.
Stage 1 NREM
Explanation:
<em>The process of firmly falling asleep has four stages through which a person goes.</em>
<em>It goes from being awake over light sleep and falling firmly into sleeping.</em>
(STAGE 1)
This is a stage in which there are non-rapid movements of the eyes. In other words, it is a process of dreamless sleep. You enter this stage the moment you decide to sleep and shut your eyes. After several minutes, your body is in fact in the sleeping mode, but not entirely. This means that you can easily be woken up without being aware that you have slept.
Features:
- <em>You can easily awake</em>
- <em>Your may roll and they may be a little open</em>
- <em>The blood pressure and the temperature of the brain start to decrease </em>
- <em>You experience the natural human reflexes that the brain sends to assure that the place of your sleep is in a safe environment. By sending twitches to your muscles, your brain may awake your body for several seconds which comes in handy if you are tired and close to sleep on work or some dangerous place like a cliff for example.</em>
- <em>Your breading starts to slow down alongside with your pressure and temperature, and your heartbeats slow down.</em>
Answer:
Reaction is 20N.
Explanation:
In general, Newton's third law of motion explains that when a force is applied on an object, a reaction of equal magnitude applies in the reverse direction of the force.
i.e F = -R
This implies that, reaction is a force in the opposite direction to that of the force applied.
Force can also be related to the weight of an object as;
F = W = mg
Thus to prevent the 20N stone from falling, a force of 20N is applied in the opposite direction. So the reaction, R is 20N.
Answer:
a. 5 × 10¹⁹ protons b. 2.05 × 10⁷ °C
Explanation:
Here is the complete question
A beam of protons is moving toward a target in a particle accelerator. This beam constitutes a current whose value is 0.42 A. (a) How many protons strike the target in 19 seconds? (b) Each proton has a kinetic energy of 6.0 x 10-12 J. Suppose the target is a 17-gram block of metal whose specific heat capacity is 860 J/(kg Co), and all the kinetic energy of the protons goes into heating it up. What is the change in temperature of the block at the end of 19 s?
Solution
a.
i = Q/t = ne/t
n = it/e where i = current = 0.42 A, n = number of protons, e = proton charge = 1.602 × 10⁻¹⁹ C and t = time = 19 s
So n = 0.42 A × 19 s/1.602 × 10⁻¹⁹ C
= 4.98 × 10¹⁹ protons
≅ 5 × 10¹⁹ protons
b
The total kinetic energy of the protons = heat change of target
total kinetic energy of the protons = n × kinetic energy per proton
= 5 × 10¹⁹ protons × 6.0 × 10⁻¹² J per proton
= 30 × 10⁷ J
heat change of target = Q = mcΔT ⇒ ΔT = Q/mc where m = mass of block = 17 g = 0.017 kg and c = specific heat capacity = 860 J/(kg °C)
ΔT = Q/mc = 30 × 10⁷ J/0.017 kg × 860 J/(kg °C)
= 30 × 10⁷/14.62
= 2.05 × 10⁷ °C
