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4 years ago

A kid moving 3.18 m/s jumps on a slip and slide(Uk=0.0751). How far has he slid when his velocity is reduced to 2.00 m/s?

1 answer:

7 0

F=ma (Newton's second law of motion).

Then,
a = F/m = Uk*mg/m = Uk*g = 0.0751*9.81 = 0.737 m/s^2 (should be negative since a deceleration is expected).

v = Sqrt (u^2-2ad), Where v = final velocity, u=initial velocity, a = acceleration, d = distance moved.

Therefore,

v^2-u^2 = -2ad => d = (v^2-u^2)/-2a = (2^2-3.18^2)/-2*0.737 = 4.15 m

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A solenoid with 400 turns has a radius of 0.040 m and is 40 cm long. If this solenoid carries a current of 12 A, what is the mag

spin [16.1K]

Answer:

The magnitude of the magnetic field inside the solenoid is 1.5 × 10⁻²T

Explanation:

Given that,

Length = 40 cm

Radius = 0.040 cm

Number of turns = 400

Current = 12 A

We need to calculate the magnetic field

Using formula of magnetic field inside the solenoid

$B =\mu nIB =\mu\dfrac{N}{l}I$

Where, $\dfrac{N}{l}$ =Number of turns per unit length

I = current

B = magnetic field

Put the value into the formula

$B =4\pi\times10^{-7}\times\dfrac{400}{40\times10^{-2}}\times12B = 1.5\times10^{-2}\ T$

Hence, The magnitude of the magnetic field inside the solenoid is 1.5 × 10⁻²T

6 0

3 years ago

Sunlight is reflected off of a puddle of water ahead of a driver. The index of refraction of the water is 1.333. If a driver sit

Lynna [10]

Answer:

option C is correct

distance from the driver is 2 m

Explanation:

Given data

index of refraction of the water n = 1.333

driver height from ground= 1.5 m

to find out

What angle does light become maximally polarized and what distance from the driver will polarized

solution

we know that n1 for water = 1.33 and we know for air n2 = 1

so tan(θ) = n1 / n2

tan(θ) = 1.33 / 1

so (θ) = 53.06 degree

so for distance d will be calculate as

tan ( 90 - (θ) ) = height / distance

tan ( 90 - 53.06 ) = 1.5 / distance

distance = 1.5 / 0.7519

distance = 1.994 m = 2 m

so option C is correct

distance from the driver is 2 m

5 0

3 years ago

An electron of mass 9.11 1031 kg has an initial speed of 3.00 105 m/s. It travels in a straight line, and its speed increases to

elena55 [62]

Explanation:

It is given that,

Mass of an electron, $m=9.11\times 10^{-31}\ kg$

Initial speed of the electron, $u=3\times 10^5\ m/s$

Final speed of the electron, $v=7\times 10^5\ m/s$

Distance, d = 5 cm = 0.05 m

(a) The acceleration of the electron is calculated using the third equation of motion as :

$a=\dfrac{v^2-u^2}{2d}$

$a=\dfrac{(7\times 10^5)^2-(3\times 10^5)^2}{2\times 0.05}$

$a=4\times 10^{12}\ m/s^2$

Force exerted on the electron is given by :

$F=m\times a$

$F=9.11\times 10^{-31}\times 4\times 10^{12}$

$F=3.64\times 10^{-18}\ N$

(b) Let W is the weight of the electron. It can be calculated as :

$W=mg$

$W=9.11\times 10^{-31}\times 9.8$

$W=8.92\times 10^{-30}\ N$

Comparison,

$\dfrac{F}{W}=\dfrac{3.64\times 10^{-18}}{8.92\times 10^{-30}}$

$\dfrac{F}{W}=4.08\times 10^{11}$

Hence, this is the required solution.

8 0

4 years ago

A car accelerates uniformly from rest and reaches a speed of 22.5 m/s in 8.96 s. Assume the diameter of a tire is 58.9 cm. (a) F

Murljashka [212]

Answer:

54.4747649021

38.2003395586 rad/s

Explanation:

Acceleration

$v=u+at\\\Rightarrow a=\dfrac{v-u}{t}\\\Rightarrow a=\dfrac{22.5-0}{8.96}\\\Rightarrow a=2.51116071429\ m/s^2$

Distance covered

$s=ut+\dfrac{1}{2}at^2\\\Rightarrow s=0\times t+\dfrac{1}{2}\times 2.51116071429\times 8.96^2\\\Rightarrow s=100.8\ m$

Number of revolutions

$n=\dfrac{s}{\pi d}\\\Rightarrow n=\dfrac{100.8}{\pi 0.589}\\\Rightarrow n=54.4747649021$

Number of revolutions is 54.4747649021

Angular speed is given by

$\omega=\dfrac{v}{r}\\\Rightarrow \omega=\dfrac{22.5}{0.589}\\\Rightarrow \omega=38.2003395586\ rad/s$

The final angular speed is 38.2003395586 rad/s

8 0

4 years ago

During a safety crash, a car impacts a solid concrete barrier and and comes to rest in 0.10s. In a second test, an identical car

kirill [66]

Answer:

The correct answer is C

Explanation:

Change is momentum can be described as the change in the product of mass and velocity of a body. Every moving object as a momentum and the higher the momentum of this object, the harder it is to stop. Impulse (a force), which is sometimes used to describe change in momentum can be described as the product as force multiplied by time.

From the description above, it can be deduced that an increase in impulse can lead to a greater change in momentum. And an increase in impulse can be brought about by an increase in the time it takes a body to be brought to rest after collision. And since the car that hit the water barrels was brought to rest at a longer time, it has a greater change in momentum

8 0

3 years ago