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WITCHER [35]
4 years ago
11

A car is moving down a flat, horizontal highway at a constant speed of 21 m/s when suddenly a rock dropped from rest straight do

wn from a bridge crashes through the windshield. The rock strikes the windshield at a right angle, and the windshield makes a 60 degree angle with the horizontal.
a. Find the speed of the rock relative to the car when it hits the windshield.
b. Find the distance above the point of contact with the windshield from which the rock was dropped.
c. If the driver had seen what was about to happen just as the rock was being released, how much time would she have had to react before the rock strikes the windshield?
Physics
1 answer:
Naddik [55]4 years ago
7 0

Answer:

a)9.8

Explanation:

because any object falling from any height is 9.8

(sorry that's the only one i know)

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As a train enters the station it slows down from 40 m/s to a 10 m/s in 5 seconds
lora16 [44]

Answer:

See the answers below.

Explanation:

To solve this problem we must use the following equation of kinematics.

v_{f}=v_{o}-a*t

where:

Vf = final velocity = 10 [m/s]

Vo = initial velocity = 40 [m/s]

t = time = 5 [s]

a = acceleration [m/s²]

Now replacing:

10=40-a*5\\40-10=a*5\\30=5*a\\a=6[m/s^{2}]

Note: The negative sign in the above equation means that the velecity is decreasing.

2)

To solve this second part we must use the following equation of kinematics.

v_{f}^{2} =v_{o}^{2} -2*a*x\\

where:

x = distance [m]

(10)^{2} =(40)^{2} -2*6*x\\100=1600-12*x\\12*x=1600-100\\12*x=1500\\x=125[m]

7 0
3 years ago
the image of a mountain can be seen on the surface of calm water. what property of light is demonstrated?
Valentin [98]
<span>I say it's the regular reflection</span>
3 0
3 years ago
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You have a large flashlight that takes 4 D-cell batteries, each with a voltage of 1.5 volts. If the current in the flashlight is
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Ohm's law states that,
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The answer is letter B. 0.75 ohms. 
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3 years ago
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What's is the power output of an engine that does 60000 J of work in 10 seconds​
ad-work [718]
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Drupady [299]

Answer:

The hot coffee has a higher temperature, but not a greater internal energy. Although the iceberg has less internal energy per mass, its enormously greater mass gives it a greater total energy than that in the small cup of coffee.

Explanation:

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3 years ago
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