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3 years ago

Why do your legs appear shorter when standing in water

1 answer:

8 0

It is because of refraction caused in water. There is difference in the medium between water and air so because of that refraction takes place. Due to this, a person’s legs appear to be shorter to our eyes. Hope this helps!

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Help with either I don’t understand this I know W=f*d but don’t get how it applies here

rosijanka [135]

Answer:

5) Displacement = +3.125 m

Displacement is in the same direction as the force vector.

6) Force = -53.89 N

Force is in an opposite direction relative to the displacement.

Explanation:

5) We are given;

Force; F = 160 N.

Workdone; W = +500 J

Now, formula for workdone is;

W = Force × displacement

Thus, displacement = Work/force

Displacement = 500/160

Displacement = +3.125 m

Thus, displacement is in the same direction as the force vector.

6) We are given;

Displacement; d = 18 m.

Workdone; W = -970 J

Like in the first answer above,

Workdone = Force × Displacement

Thus;

Force = Workdone/Displacement

Force = -970/18

Force = -53.89 N

Since force is negative and displacement is positive, it means force is in an opposite direction relative to the displacement.

3 0

3 years ago

An inattentive driver is traveling 18.0 m/s when he notices a red light ahead. his car is capable of decelerating at a rate of 3

ryzh [129]

Speed of the car given initially

v = 18 m/s

deceleration of the car after applying brakes will be

a = 3.35 m/s^2

Reaction time of the driver = 0.200 s

Now when he see the red light distance covered by the till he start pressing the brakes

$d_1 = v* t$

$d_1 = 18* 0.200 = 3.6 m$

Now after applying brakes the distance covered by the car before it stops is given by kinematics equation

$v_f^2 - v_i^2 = 2 a s$

here

vi = 18 m/s

vf = 0

a = - 3.35

so now we will have

$0^2 - 18^2 = 2*(-3.35)(s)$

$s = 48.35 m$

So total distance after which car will stop is

$d = d_1 + d_2$

$d = 48.35 + 3.6 = 51.95 m$

So car will not stop before the intersection as it is at distance 20 m

3 0

3 years ago

On the Celsius scale, at what temperature does water boil?

Anuta_ua [19.1K]

The answer is 100 my nilla.

6 0

3 years ago

A 200g piece of iron is heated at 100C. It is than dropped into water to bring its temperature down to 22C. What is the amount o

gizmo_the_mogwai [7]

Answer:

6926.4J

Explanation:

Given parameters:

Mass of iron = 200g

Initial temperature = 100°C

Final temperature = 22°C

Unknown:

Amount of heat transferred to the water = ?

Solution:

The quantity of heat transferred to the water is a function of mass and temperature of the iron;

H = m c Ф

m is the mass of the iron

Ф is the change in temperature

C is the specific heat capacity of iron = 0.444 J/g°C

Now;

insert the parameters and solve;

H = 200 x 0.444 x (100-22)

H = 6926.4J

8 0

3 years ago

A convex mirror has a focal length of 15cm. If the object is 35cm from the mirror and is 2cm tall, what is the magnification? Ro

Verizon [17]

Answer:

The magnification is 0.3

Explanation:

Given:

The focal length of the convex mirror, f = 15 cm

for convex mirror f = -f = -15 cm

The distance of object, u = 35 cm

Height of the object, h = 2 cm

Now, using the mirror formula, we have

$\frac{1}{f}=\frac{1}{u}+\frac{1}{v}$

where, v is the distance of the image

on substituting the values, we get

$\frac{1}{-15}=\frac{1}{35}+\frac{1}{v}$

$-\frac{1}{v}=\frac{1}{35}-\frac{1}{-15}$

v = -10.5 cm

now, the magnification (m) is given as:

m = $-\frac{v}{u}$

on substituting the values, we get

m = $-\frac{-10.5}{35}$

m = 0.3

Hence, the magnification is 0.3

6 0

3 years ago