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2 years ago

What is the best definition of

Physics

1 answer:

Brut [27]2 years ago

7 0

Answer:

Work is best defined as a force exerted on a body to cause it move over a certain distance.

work=force×displacement×cosθ

Explanation:

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7. Which of the following is NOT always true about a synthesis reaction!

Rainbow [258]

Answer:

Explanation:

the formula is a + b = ab

5 0

3 years ago

A rectangular dam is 101 ft long and 54 ft high. If the water is 35 ft deep, find the force of the water on the dam (the density

blsea [12.9K]

To solve this problem we will begin by finding the pressure through density and average depth. Later we will find the Force, by means of the relation of the pressure and the area.

$P = \rho h$

Here,

h = Depth average

$\rho$ = Density

Moreover,

$\text{Density of water}= \rho = 62.4lb/ft^3$

Replacing,

$P = (62.4lb/ft^3)(\frac{35}{2}ft)$

$P = 1092 lb/ft^2$

Finally the force

$\text{Force} = \text{Pressure}\times \text{Area of dam with water acting on it}$

$F = 1092lb/ft^2(101ft*52ft)$

$F = 5.735*10^6lbf$

6 0

3 years ago

Daniel steps on the gas pedal of his car, and the engine increases its performance from zero to

RSB [31]

Answer

The frequency and the period are 45 cycles/second and 0.023 seconds

Explanation:

The frequency of the engine is given by :

$f=\dfrac{rpm}{60}$

We have, the engine increases its performance from zero to 2700 rpms.

Frequency,

$f=\dfrac{2700}{60}\ \text{cycles per second}\\\\f=45\ \text{cycles per second}$

The time period of the engine is given by :

T = f/f

So,

$T=\dfrac{1}{45}\ s\\\\T=0.023\ s$

Hence, the required frequency and the period are 45 cycles/second and 0.023 seconds respectively.

6 0

3 years ago

Two point sources, vibrating in phase, produce an interferencepattern in a ripple tank. If the frequency is increased by 20%, th

Vera_Pavlovna [14]

Answer:

option A

Explanation:

given,

frequency is increased by 20%

we know,

$\dfrac{x_n}{L}d = (n-\dfrac{1}{2})\times \lambda$ ...........(1)

where

x_n is the perpendicular distance between the point the interference pattern is obtained,

L is the distance between the center of the two point sources

and λ is the wavelength of light.

If the frequency is increased by 20%, then the number of nodal lines is increased by 20%.

From equation (1),we observe that the frequency is directly proportional to the number of nodal lines.

Hence, the correct answer is option A

8 0

3 years ago

A stone is thrown from the top of a building 30m high. If it strikes the ground at an angle 45, with what speed was it thrown?

sasho [114]

Answer:

24.2 m/s

Explanation:

The stone strikes the ground at an angle of 45 degrees: this means that its vertical velocity is equal (in magnitude) to its horizontal velocity, in fact:

$tan \theta = \frac{|v_y|}{v_x}\\tan 45^{\circ} = 1 \rightarrow |v_y| = v_x$

The motion along the vertical direction is a uniformly accelerated motion, so we can find the final vertical velocity using the following suvat equation

$v_y^2 -u_y^2 = 2as$

where

$v_y$ is the final vertical velocity

$u_y = 0$ is the initial vertical velocity (zero because the stone is thrown horizontally)

$a=g=9.8 m/s^2$ is the acceleration of gravity (we take downward as positive direction)

s = 30 m is the vertical displacement

Solving for vy,

$v_y = \sqrt{u_y^2+2as}=\sqrt{0+2(9.8)(30)}=24.2 m/s$

This means that the horizontal velocity is also 24.2 m/s: and since the horizontal velocity is constant during the whole motion (there is no acceleration in the horizontal direction), this means that the stone was thrown exactly at 24.2 m/s.

7 0

3 years ago