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slamgirl [31]
3 years ago
10

a car is traveling at 20 meters/seconds anf is brought to rest by applying breaks over a period of 4 seconds. what is its averag

e acceleration over this time in time interval​
Physics
1 answer:
allochka39001 [22]3 years ago
8 0

Answer:

<em>2.5m/s²</em>

Explanation:

Given the following:

Initial velocity u = 0m/s

Final velocity v = 20m/s

Time t = 4s

Required

average acceleration over this time in time interval​

Using the equation of motion

v = u + at

10 = 0 + a(4)

10 = 4a

a = 10/4

a = 2.5m/s²

<em>Hence its average acceleration over this time in time interval​ is 2.5m/s²</em>

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Two balloons (m = 0.021 kg) are separated by a distance of d = 16 m. They are released from rest and observed to have an instant
evablogger [386]

(a) 2.56\cdot 10^{-5} C

According to Newton's second law, the force experienced by each balloon is given by:

F = ma

where

m = 0.021 kg is the mass

a = 1.1 m/s^2 is the acceleration

Substituting, we found:

F=(0.021)(1.1)=0.0231 N

The electrostatic force between the two balloons can be also written as

F=k\frac{Q^2}{r^2}

where

k is the Coulomb's constant

Q is the charge on each balloon

r = 16 m is their separation

Since we know the value of F, we can find Q, the magnitude of the charge on each balloon:

Q=\sqrt{\frac{Fr^2}{k}}=\sqrt{\frac{(0.0231)(16)^2}{9\cdot 10^9}}=2.56\cdot 10^{-5} C

(b) 1.6\cdot 10^{14} electrons

The magnitude of the charge of one electron is

e=1.6\cdot 10^{-19}C

While the magnitude of the charge on one balloon is

Q=2.56\cdot 10^{-5} C

This charge can be written as

Q=Ne

where N is the number of electrons that are responsible for this charge. Solving for N, we find:

N=\frac{Q}{e}=\frac{2.56\cdot 10^{-5}}{1.6\cdot 10^{-19}}=1.6\cdot 10^{14}

5 0
3 years ago
One student did an experiment with two unknown minerals, Mineral 1 and Mineral 2. The hardness scale shown below was used for th
Umnica [9.8K]
Scale: (soft 1-->6 hardest)
<span>1=Talc 2=Gypsum 3=Calcite 4=Fluorite 5=Apatite 6=Orthoclase

</span>Mineral #1 can only scratch two other minerals therefore it must have a hardness level of 2+1=3 which is Calcite. (scratches talc, gypsum)

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Looking through the possible conclusions.. It looks like answer is D.


3 0
3 years ago
If a rock is dropped from the top of a tower at the front of it and takes 3.6 seconds to hit the ground. Calculate the final vel
expeople1 [14]

Answer:

35.28m/s; 63.50m

Explanation:

<u>Given the following data;</u>

Time, t = 3.6 secs

Since it's a free fall, acceleration due to gravity = 9.8m/s²

Initial velocity, u = 0

To find the final velocity, we would use the first equation of motion;

V = u + at

Substituting into the equation, we have;

V = 0 + 9.8 * 3.6

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Therefore, the final velocity of the penny is 35.28m/s.

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S = ut + \frac {1}{2}at^{2}

Substituting the values into the equation;

S = 0(3.6) + \frac {1}{2}*9.8*(3.6)^{2}

S = 0 + 4.9*12.86

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Therefore, the height of the tower is 63.50m.

6 0
3 years ago
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dybincka [34]

Answer:

1.95m/s

Explanation:

Please view the attached file for the detailed solution.

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6 0
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3 0
3 years ago
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