Answer:
F = 69.5 [N]
Explanation:
We must remember that the friction force is defined as the product of the normal force by the coefficient of friction, and it can be calculated by the following expression.
[tex]f=N*miu[/tex]
where:
N = normal force [N]
miu = friction coefficient
f = friction force = 22 [N]
Now we must calculate the force exerted by means of Newton's second law which tells us that the sum of forces on a body is equal to the product of mass by acceleration.
[tex]F - f = m*a[/tex]
where:
F = force exerted [N]
f = friction force [N]
m = mass = 95 [kg]
a = acceleration = 0.5 [m/s²]
Now replacing:
[tex]F - 22 = 95*0.5\\F = 47.5 + 22\\F = 69.5 [N][/tex]
. A ventilation fan has blades 0.25 m long rotating at 20 rpm (revolutions per minute). What is the centripetal acceleration of a point on the outer tip of a blade
Answer:
The centripetal acceleration of a point on the outer tip of a blade is 1.097 m/s²
Explanation:
Given;
length of the fan blade, r = 0.25 m
angular speed = 20 rpm
The angular speed in rad/s is given as;
[tex]\omega = \frac{20 \ rev}{ \ \ \min} \ \times \ \frac{2\pi}{1 \ rev} \ \times \ \frac{1 \ \min}{60s} = 2.095 \ rad/s \\\\[/tex]
The centripetal acceleration of a point on the outer tip of a blade is given as;
[tex]\alpha_c = \frac{v^2}{r} = \omega ^2r[/tex]
[tex]\alpha _c = (2.095)^2(0.25)\\\\\alpha _c =1.097 \ m/s^2[/tex]
Therefore, the centripetal acceleration of a point on the outer tip of a blade is 1.097 m/s²
Answer:
The centripetal acceleration = [tex]1.1m/s^2[/tex]Explanation:
Given
[tex]rpm = 20[/tex]
therefore,
[tex]20rpm = \frac{20*2\pi}{60}\\\\=2.1 rad/s = w[/tex]
From,
[tex]V = rw\\\\V = 0.25 * 2.1\\\\V = 0.525m/s[/tex]
Centripetal acceleration,
[tex]a_c = \frac{V^2}{r}\\\\a_c = \frac{0.525^2}{0.25}\\\\a_c = 1.1m/s^2[/tex]
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Dominic has a brain injury. Why is this MOST likely to be a serious injury?
If Dominic has a brain injury, then he must have sustained a serious injury.
Functions of the brainThe brain coordinates all the activities in the body such as speech, locomotion, coordination and intelligence. This makes the brain the master point of control in the body.
Brain injuryWhenever there is an injury to the brain, various parts of the body could be affected. Functions such as speech, locomotion and general coordination may become largely impaired.
Therefore, if Dominic has a brain injury, then he must have sustained a serious injury.
Learn more about the brain: https://brainly.com/question/5361122
the amplitude of an oscillator decreases to 36.8% of its initial value in 10.0 s. what is the value of the time constant
Answer:
τ = 5 s
Explanation:
When a vibrating body is damped. Its amplitude starts to decrease. This decrement is exponential. And it is given as follows:
[tex]X = X_{0}e^{-\frac{t}{2\tau}[/tex]
where,
τ = Time Constant = ?
X = Instantaneous value of amplitude
X₀ = Initial Value of amplitude
t = time interval = 10 s
The ratio of decrement is given as:
[tex]\frac{X}{X_0} = 36.8\% = 0.368[/tex]
therefore, using these values, we get:
[tex]\frac{X}{X_{0}} = 0.368 = e^{\frac{10\ s}{2\tau}}[/tex]
Taking natural log (ln) on both sides, we get:
[tex]ln(0.368) = \frac{10\ s}{2\tau}\\\\\tau = \frac{10\ s}{2ln(0.368)}[/tex]
τ = 5 s
The value of the time constant for the decrease in the amplitude of this oscillator is 5.
Given the following data:
Decrease in amplitude = 36.8% = 0.368Time = 10.0 seconds.To determine the value of the time constant:
Mathematically, the amplitude for damped harmonic motion is given by the formula:
[tex]X = X_o e^\frac{t}{2 \tau}[/tex]
Where:
t is the time.[tex]\tau[/tex] is the time constant.X is the instantaneous value of amplitude.[tex]X_o[/tex] is the initial value of amplitude.Rearranging the formula, we have:
[tex]\frac{X}{X_o} = e^{-\frac{t}{2 \tau}}[/tex]
Substituting the given parameters into the formula, we have;
[tex]0.368 = e^\frac{-10}{2 \tau}\\\\ln(0.368) = \frac{-10}{2 \tau}\\\\-0.9997 = \frac{-10}{2 \tau}\\\\2 \tau \times -0.9997 = 10\\\\-1.9994\tau=-10\\\\\tau =\frac{-10}{-1.9994} \\\\\tau = 5.0[/tex]
Time constant = 5
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