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3 years ago

A force has direction and contact

Physics

1 answer:

dalvyx [7]3 years ago

7 0

Answer:

A force has both magnitude and direction, making it a vector quantity. It is measured in the SI unit of newton (N). Force is represented by the symbol F. The original form of Newton's second law states that the net force acting upon an object is equal to the rate at which its momentum changes with time.

Other units: dyne, pound-force, poundal, kip, kilopond

SI unit: newton (N)

Common symbols: F→, F, F

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based on your reading "take a closer look" what can you say about the image that forms on the retina of your eye?

shepuryov [24]

Answer:

it is an upside-down image but the brain realizes it and corrects it in its orientation so we see it in right direction.

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3 years ago

Read 2 more answers

A tennis ball is thrown horizontally at a speed of 10 m/s from the top of a building 78.4 meters high. how long does it take the

cupoosta [38]

When it comes to horizontal projectiles, the formula for time is:

$t = \sqrt{ \frac{2dy}{g} }$

Where:
dy = vertical distance or height
g = acceleration due to gravity
t = time

Based on the problem, we know that the height at which the tennis ball was thrown is 78.4 m and the acceleration due to gravity is a constant 9.8m/s2. All you need to do is input that into our equation:
$t = \sqrt{ \frac{2dy}{g} }$
$t = \sqrt{ \frac{(2)(78.4m)}{9.8m/s^{2}} }$
$t = \sqrt{ \frac{156.8m}{9.8m/s^{2}} }$
$t = \sqrt{16s^{2}}$
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The time it would take is 4 seconds.

7 0

4 years ago

cylindrical electric resistance heater has a diameter of 1cm and length of 0.25m. When air at 25oC flows across the heater a hea

kirza4 [7]

Answer:

Explanation:

From the information given:

The diameter of the cylindrical heater (d) = 1 cm

The length of the cylindrical heater (l) = 0.25 m

The ambient air temperature $(T_{\infty})$ = 25° C= (273+25)K = 298 K

The convective heat transfer coefficient (h) = 25 W/m² °C

The electric input Q = 5W

As stated in the question that if radiation is being neglected:-

Let also assume that;

the heat transfer takes place at a steady-state

1-D flow takes place

No external heat generation; &

No force convection takes place;

Then; the heat transfer through the convection can be calculated as:

$Q = hA(T - T_{\infty})$

$5= 25 \times (\pi \times (1\times 10^{-2}) \times 0.25) (T -0.25)$

By solving the above calculation:

T ( surface temperature of the heater) = 50.46° C 122.83° F

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3 years ago

The temperature of a substance depends on what two types of energy

Bezzdna [24]

Answer:

Thermal and kinetic.

Explanation:

Thermal energy is the energy generated by heat. Kinetic energy is the movement of particles in a substance which is responsible for the heat increase.

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3 years ago

Find the exponent A in the equation

hodyreva [135]

Start by swapping the variables in the equations with their units (leave A alone for now): $v=\frac{a^2t^A}{x} \Rightarrow \frac{L}{T} = \frac{ (\frac{L}{T^2})^2 T^A }{L}$

Multiply by L and square the fraction: $\frac{L^2}{T} = \frac{L^2}{T^4} T^A \Rightarrow \frac{L^2}{T} \div \frac{L^2}{T^4}=T^A$

Divide the fraction by multiplying by the reciprocal: $\frac{L^2}{T} \times \frac{T^4}{L^2} = T^A \Rightarrow T^3=T^A$

Therefore A=3

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4 years ago