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Elenna [48]
2 years ago
10

A rock is dropped straight down from roof. It hits the ground with a velocity of 28.2 m/sec. How high was the roof, and how long

did it take to hit the ground?
Physics
1 answer:
notsponge [240]2 years ago
6 0

Answer:

18 secs

Explanation:

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Gas "floats" so if there are examples or pictures it would be the one with the most evenly spread out "dots". 
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The action of two forces. One is a forward force of 1157 N provided by traction between the wheels and the road. The other is a
Pie

Complete question

A 2700 kg car accelerates from rest under the action of two forces. one is a forward force of 1157 newtons provided by traction between the wheels and the road. the other is a 902 newton resistive force due to various frictional forces. how far must the car travel for its speed to reach 3.6 meters per second? answer in units of meters.

Answer:

The car must travel 68.94 meters.

Explanation:

First, we are going to find the acceleration of the car using Newton's second Law:

\sum\overrightarrow{F}=m\overrightarrow{a} (1)

with m the mass , a the acceleration and \sum\overrightarrow{F} the net force forces that is:

(F-f) (2)

with F the force provided by traction and f the resistive force:

(2) on (1):

(F-f)=ma

solving for a:

a=\frac{F-f}{m} =\frac{1157N-902N}{2700kg} =0.094\frac{m}{s^{2}}

Now let's use the Galileo’s kinematic equation

Vf^{2}=Vo^{2}+2a\varDelta x (3)

With Vo te initial velocity that's zero because it started from rest, Vf the final velocity (3.6) and \varDelta x the time took to achieve that velocity, solving (3) for \varDelta x:

\varDelta x= \frac{Vf^{2}}{2a} = t= \frac{(3.6\frac{m}{s})^2}{2*0.094\frac{m}{s^{2}}}

t=68.94 m

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3 years ago
In the Bohr model of the atom, an electron in an orbit has a fixed ____.
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Calculate the wavelength of violet light with a frequency of 750×10 to the 12
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Wavelength of any wave = (speed) / (frequency)

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Wavelength = 3 x 10 to the 8 / 750 x 10 to the 12 = 4 x 10 to the -7 or 400 nanometers.
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3 years ago
Read 2 more answers
2. What do you understand by balanced and unbalanced force​
labwork [276]

Answer:

forces that are equal in size and opposite in direction. Balanced forces do not result in any change in motion. unbalanced. forces: forces applied to an object in opposite directions that are not equal in size. Unbalanced forces result in a change in motion.

\\

hope helpful ~

8 0
2 years ago
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