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2 years ago

Why can concave mirror is used in cosmetic mirror

Physics

1 answer:

tatuchka [14]2 years ago

4 0

Answer:

"When face is placed between the concave mirror and its focus, it produces a magnified image. This enlarged image of face is helpful in makeup as even pores of skin are clearly visible."

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Displacement vectors of 4km north, 2km south, 5km north, 5km south combine to a total displacement of

goldfiish [28.3K]

Answer

The combined displacement is 2km north

Explanation

Since displacement is a vector quantity, we take into account the direction.

Good for us all the displacement vectors are in the same dimension, so we can make north positive and south negative or vice-versa.

We now add to obtain,

$4+-2+5+-5$

This will simplify to

$=4-2+5-5=2$

Therefore the combined displacement is 2km north

5 0

2 years ago

A ball is dropped from the top of a 77 m building. With what speed does the ball hit the ground? _________ m/s

vitfil [10]

Answer:

38.87 m/s

Explanation:

Given that the ball is dropped from a height = 77 m

u = 0 m/s

s = 77 m

a = g = 9.81 m/s²

Applying the expression as:

$v^2-u^2=2as$

Applying values as:

$v^2-u^2=2as\\\Rightarrow v=\sqrt{2as+u^2}\\\Rightarrow v=\sqrt{2\times 9.81\times 77+0^2}\\\Rightarrow v=38.87\ m/s$

The speed with which the ball hit the ground = 38.87 m/s

3 0

2 years ago

An object begins x=75.2 m and undergoes a displacement of -48.7 m. what is its final position?

xz_007 [3.2K]

Answer:

26.5 m

Explanation:

$x_{o}$ = initial position of the object = 75.2 m

$x$ = final position of the object

$d$ = displacement of the object = - 48.7

Displacement of the object is given as the difference of final and initial position of the object

$d = x - x_{o}$

Inserting the values

- 48.7 = x - 75.2

x = 26.5 m

8 0

2 years ago

A 40 kg dog is sitting on top of a hillside and has a potential energy of 1,568 J. What is the height of the hillside? (Formula:

igomit [66]

Answer:

B) 4.0

Explanation:

Jus took the test on E D G E

5 0

2 years ago

Read 2 more answers

An airplane has an effective wing surface area of 17.0 m2 that is generating the lift force. In level flight the air speed over

olga_2 [115]

To solve this problem it is necessary to apply the equations given from Bernoulli's principle, which describes the behavior of a liquid moving along a streamline. Mathematically this expression can be given as,

$P_1 + \frac{1}{2}\rho*v_1^2 + P_2 + \frac{1}{2}*\rho*v_2^2=0$

Where,

$P_i =$ Pressure at each state

$\rho$ = Density

$v_i =$ Velocity

Re-organizing the expression we can get that

$P_1 - P_2 = \frac{1}{2}\rho (v_2^2 - v_1^2)$

Our values are given as

$v_1 = 40m/s$

$v_2 = 55m/s$

$\rho_{water} = 1.2kg/m^3 \rightarrow$ Normal Conditions

Replacing we have,

$P_1 -P_2 = \frac{1}{2}*1.2*(55^2-40^2)$

$P_1 - P_2 = 855Pa$

If we consider that there is a balance between the two states, the Force provided by gravity is equivalent to the Support Force, therefore

$F_l = F_g$

Here the lift force is the product between the pressure difference previously found by the effective area of the aircraft, while the Force of gravity represents the weight. There,

$F_g = W$