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3 years ago

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A 70kg man is moving with a speed of 3.2 m/s on a rough surface, his speed was decreasing uniformly until he reaches to a stop b

ecause of the friction of the rough surface. Calculate the friction force exerted on the man.

1 answer:

VMariaS [17]3 years ago

6 0

Answer:

224 N

Explanation:

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An airplane wing is designed so that the speed of the air across the top of the wing is 255 m/s when the speed of the air below

grin007 [14]

<h2>Answer:442758.96N</h2>

Explanation:

This problem is solved using Bernoulli's equation.

Let $P$ be the pressure at a point.

Let $p$ be the density fluid at a point.

Let $v$ be the velocity of fluid at a point.

Bernoulli's equation states that $P+\frac{1}{2}pv^{2}+pgh=constant$ for all points.

Lets apply the equation of a point just above the wing and to point just below the wing.

Let $p_{up}$ be the pressure of a point just above the wing.

Let $p_{do}$ be the pressure of a point just below the wing.

Since the aeroplane wing is flat,the heights of both the points are same.

$\frac{1}{2}(1.29)(255)^{2}+p_{up}= \frac{1}{2}(1.29)(199)^{2}+p_{do}$

So, $p_{up}-p_{do}=\frac{1}{2}\times 1.29\times (25424)=16398.48Pa$

Force is given by the product of pressure difference and area.

Given that area is $27ms^{2}$ .

So,lifting force is $16398.48\times 27=442758.96N$

6 0

3 years ago

planet a has twice the mass of planet b. from this info what can we conclude about the acceleration due to gravity at the surfac

tangare [24]

Answer: acceleration due to gravity of planet a would be twice that of planet b. Given that the radius are thesame.

Explanation:

Acceleration due to gravity is as a result of the gravitational force of attraction of a planet to its centre.

g = GM/r^2

Where;

g = acceleration due to gravity

G = gravitational constant

M = mass of planet

r = radius of planet

Given that the two planet have the same radius, if the mass of planet a is twice the mass of planet b the the acceleration due to gravity of planet a would be twice that of planet b, because acceleration due to gravity is directly proportional to the mass of the planet.

6 0

3 years ago

A resistor and an inductor are connected in series to a battery. The battery is suddenly removed from the circuit. The time cons

Vladimir79 [104]

E, 63% of the value. I forget the rationale behind it but I learnt that in engineering. 90% confident for that answer.

3 0

3 years ago

Read 2 more answers

Use Hooke's Law, which states that the distance a spring stretches (or compresses) from its natural, or equilibrium, length vari

Phantasy [73]

Answer:

706.68 N

Explanation:

By Hooke's law,

$F = ke$

$k=\dfrac{F}{e}$

Using the values in the question,

$k=\dfrac{265\text{ N}}{0.15 \text{ m}}=1766.7\text{ N/m}$

When e = 0.4 m,

$F = 1766.7\text{ N/m}\times0.4\text{ m}=706.68\text{ N}$

6 0

3 years ago

Remember to include your data, equation, and work when solving this problem.

andrezito [222]

Answer:

F = 0.00156[N]

Explanation:

We can solve this problem by using Newton's proposed universal gravitation law.

$F=G*\frac{m_{1} *m_{2} }{r^{2} } \\$

Where:

F = gravitational force between the moon and Ellen; units [Newtos] or [N]

G = universal gravitational constant = 6.67 * 10^-11 [N^2*m^2/(kg^2)]

m1= Ellen's mass [kg]

m2= Moon's mass [kg]

r = distance from the moon to the earth [meters] or [m].

Data:

G = 6.67 * 10^-11 [N^2*m^2/(kg^2)]

m1 = 47 [kg]

m2 = 7.35 * 10^22 [kg]

r = 3.84 * 10^8 [m]

$F=6.67*10^{-11} * \frac{47*7.35*10^{22} }{(3.84*10^8)^{2} }\\ F= 0.00156 [N]$

This force is very small compare with the force exerted by the earth to Ellen's body. That is the reason that her body does not float away.

6 0

3 years ago