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Kazeer [188]
3 years ago
14

A driver has a reaction time of 0.50 s , and the maximum deceleration of her car is 6.0 m/s^2 . She is driving at 20 m/s when su

ddenly she sees an obstacle in the road 50 m in front of her. What is the distance she passes after noticing the obstacle before fully stopping? Express your answer with the appropriate units.
Physics
1 answer:
QveST [7]3 years ago
4 0

Answer:

The car stops after 32.58 m.

Explanation:

t = Time taken for the car to stop

u = Initial velocity = 20 m/s

v = Final velocity = 0

s = Displacement

a = Acceleration = -6 m/s²

Time taken by the car to stop

v=u+at\\\Rightarrow t=\frac{v-u}{a}\\\Rightarrow t=\frac{0-20}{-6}\\\Rightarrow t=3.33\ s

Total Time taken by the car to stop is 0.5+3.33 = 3.83 s

s=ut+\frac{1}{2}at^2\\\Rightarrow s=20\times 3.83+\frac{1}{2}\times -6\times 3.83^2\\\Rightarrow s=32.58\ m

The car stops after 32.58 m.

Distance between car and obstacle is 50-32.58 = 17.42 m

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Answer:

d=\frac{1.22\times 640\times 10^{-9}\times 21.7}{7.35\times 10^{-2}}=2305.21\times 10^{-7}m

Explanation:

The expression which represent the first diffraction minima by a circular aperture is given by d sin\Theta =1.22\lambda--------eqn 1

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As \Theta is very small so we can write sin\Theta =tan\Theta

So from eqn 1 and eqn 2 we can write

y_1=\frac{1.22\lambda D}{d}--------eqn 3

Here y_1 is the position of first maxima D is the distance of screen from the circular aperture d is the diameter of aperture

It is given that diameter of circular aperture is 14.7 cm so y_1=\frac{14.7}{2}=7.35 \ cm

Now putting all these value in eqn 3

d=\frac{1.22\lambda D}{y_1}

d=\frac{1.22\times 640\times 10^{-9}\times 21.7}{7.35\times 10^{-2}}=2305.21\times 10^{-7}m

8 0
3 years ago
Can someone please shows me the steps and answer. Urgent!
BabaBlast [244]
Using the formula t=root of 2h/g then where h=28 and g=9.8 then substitute so the answer is 2.4seconds
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3 years ago
What's a refractive medium that focuses light to a single point?
ss7ja [257]

Answer:

The convex lens is shaped so that all light rays that enter it parallel to its axis cross one another at a single point on the opposite side of the lens.

Explanation:

3 0
3 years ago
The brightest star in the night sky in the northern hemisphere is Sirius. Its distance from Earth is estimated to be 8.7 light y
katen-ka-za [31]

Answer:5.11(10)^{13}miles

Explanation:

A light year is a unit of length and is defined as "the distance a photon would travel in vacuum during a Julian year at the speed of light at an infinite distance from any gravitational field or magnetic field. "

In other words: It is the distance that the light travels in a year.  

This unit is equivalent to 5.879(10)^{12}miles, which mathematically is expressed as:

1Ly=5.879(10)^{12}miles

Doing the conversion:

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4 0
3 years ago
7. Un bloque de 700 N se encuentra sobre una viga uniforme de 200 N y 6 m de longitud. El bloque está a una distancia de 1 m del
GrogVix [38]

Answer:

 x =  0.176 m

Explanation:

For this exercise we will take the condition of rotational equilibrium, where the reference system is located on the far left and the wire on the far right. We assume that counterclockwise turns are positive.

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we apply the equation

       ∑ τ = 0

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the length of the bar is L = 6m

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let's calculate

let's use the maximum tension that resists the cable T = 900 N

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             x = - 0.176 m

Therefore the block can be up to 0.176m to keep the system in balance.

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4 years ago
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