Which biome has the most variable year round temperature

A shaving or makeup mirror is designed to magnify your face by a factor of 1.40 when your face is placed 20.0cm in front of it

Dennis_Churaev [7]

Answer:

(a) convex mirror

(b) virtual and magnified

(c) 23.3 cm

Explanation:

The having mirror is convex mirror.

distance of object, u = - 20 cm

magnification, m = 1.4

(a) As the image is magnified and virtual , so the mirror is convex in nature.

(b) The image is virtual and magnified.

(c) Let the distance of image is v.

Use the formula of magnification.

$m =-\frac{v}{u}\\1.4=-\frac{v}{-20}\\v =28 cm$

Use the mirror equation, let the focal length is f.

$\frac{1}{f}=\frac{1}{v}+\frac{1}{u}\\\frac{1}{f}=\frac{1}{28}+\frac{1}{20}\\\frac{1}{f}=\frac{28+20}{560}\\f=11.67cm$

Radius of curvature, R = 2 f = 2 x 11.67 = 23.3 cm

5 0

3 years ago

A skier leaves the horizontal end of a ramp with a velocity of 31.0 m/s and lands 156.3 m from the base of a ramp how high is th

BartSMP [9]

Answer:

The height of ramp = 124.694 m

Explanation:

Using second equation of motion,

$s = ut + \frac{1}{2}at^2$

From the question,

u = 31 m/s; s = 156.3 m, a=0

substituting values

$156.3 = 31\times t + 0$

t = $\frac{156.3}{31 }$

= 5.042 s

Similary, for the case of landing

t = 5.042 s; initial velocity, u =0

acceleration = acceleration due to gravity, g = 9.81 $m/s^2$

Substituting in $h = ut + \frac{1}{2}gt^2$

$h = 0 + \frac{1}{2} \times 9.81 \times (5.042)^2$

h = 124.694 m

So height of ramp = 124.694 m

3 0

3 years ago

Lonnie pitches a baseball of mass 0.20 kg. The ball arrives at home plate with a speed of 40 m/s and is batted straight back to

suter [353]

Answer:

B) 20N.s is the correct answer

Explanation:

The formula for the impulse is given as:

Impulse = change in momentum

Impulse = mass × change in speed

Impulse = m × ΔV

Given:

initial speed = 40m/s

Final speed = -60 m/s (Since the the ball will now move in the opposite direction after hitting the bat, the speed is negative)

mass = 0.20 kg

Thus, we have

Impulse = 0.20 × (40m/s - (-60)m/s)

Impulse = 0.20 × 100 = 20 kg-m/s or 20 N.s

4 0

3 years ago

The sound level measured in a room by a person watching a movie on a home theater system varies from 40 dB during a quiet part t

UNO [17]

Answer:

$\alpha=-3.01dB$

Explanation:

From the question we are told that:

Sound level intensity

$\triangle I=40dB-80dB$

Generally the equation for intensity level is mathematically given by

$\alpha=10log_{10}(I/I_x)dB$

Where

I= Intensity measured

$I_x=Threshold\ of\ audibility$

$I_x= 10-12 W / m2$

$\alpha= 10 log10 \frac{I_1}{I_x} - 10 log10 \frac{}I_2{I_x}$

$\alpha= 10 log10 \frac{I_1}{I_2}$

$\alpha=10 log10\frac{40}{80}$

$\alpha=-3.01dB$

7 0

3 years ago

Which parts of Dalton’s atomic theory had to be revised

eduard

The indivisibility of an atom was proved wrong an atom can be further subdivided into protons, neutrons and electrons. However an atom is the smallest particle that takes part in chemical reactions

7 0

3 years ago