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Tanzania [10]
1 year ago
14

1. A large ball was let go on a hill and started rolling down with a constant acceleration of 4.2 m/s². What was the velocity of

the ball after 12 s?​
Physics
1 answer:
pochemuha1 year ago
8 0

Answer:

<em>The velocity after 12s is 50.4m/s</em>.

Explanation:

<em>In acceleration formula make velocity the </em><em>subject.</em>

<em> acceleration(a) = velocity(</em>v)÷time(t)

<h3><em> </em><em>velocity</em><em> </em><em>(</em><em>v)</em><em> </em><em>=</em><em> </em><em>acceleration</em><em>(</em><em>a)</em><em>×</em><em>t</em><em>ime</em><em>(</em><em>t)</em></h3>

<em>V </em><em>=</em><em> </em><em>4</em><em>.</em><em>2</em><em>m</em><em>/</em><em>s²</em><em>×</em><em>1</em><em>2</em><em>s</em>

<em>V </em><em>=</em><em> </em><em>5</em><em>0</em><em>.</em><em>4</em><em>m</em><em>/</em><em>s</em>

<em>Therefore</em><em> the</em><em> </em><em>velocity</em><em> </em><em>after</em><em> </em><em>1</em><em>2</em><em>s</em><em> </em><em>is </em><em>5</em><em>0</em><em>.</em><em>4</em><em>m</em><em>/</em><em>s.</em>

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A nonconducting sphere of diameter 10.0 cm carries charge distributed uniformly inside with charge density of +5.50 µC/m3 . A pr
VLD [36.1K]

Answer:

t = 2.58*10^-6 s

Explanation:

For a nonconducting sphere you have that the value of the electric field, depends of the region:

rR:\\\\E=k\frac{Q}{r^2}

k: Coulomb's constant = 8.98*10^9 Nm^2/C^2

R: radius of the sphere = 10.0/2 = 5.0cm=0.005m

In this case you can assume that the proton is in the region for r > R. Furthermore you use the secon Newton law in order to find the acceleration of the proton produced by the force:

F=m_pa\\\\qE=m_pa\\\\k\frac{qQ}{r^2}=m_pa\\\\a=k\frac{qQ}{m_pr^2}

Due to the proton is just outside the surface you can use r=R and calculate the acceleration. Also, you take into account the charge density of the sphere in order to compute the total charge:

Q=\rho V=(5.5*10^{-6}C/m^3)(\frac{4}{3}\pi(0.05m)^3)=2.87*10^{-9}C\\\\a=(8.98*10^9Nm^2/C^2)\frac{(1.6*10^{-19}C)(2.87*10^{-9}C)}{(1.67*10^{-27}kg)(0.05m)^2}=9.87*10^{11}\frac{m}{s^2}

with this values of a you can use the following formula:

a=\frac{v-v_o}{t}\\\\t=\frac{v-v_o}{a}=\frac{2550*10^3m/s-0m/s}{9.87*10^{11}m/s^2}=2.58*10^{-6}s

hence, the time that the proton takes to reach a speed of 2550km is 2.58*10^-6 s

3 0
2 years ago
3. A motorbike travels 45 miles in 15 minutes, what is its speed?
antiseptic1488 [7]
Hes going 180 mph
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3 0
3 years ago
Landslides are primarily caused by -
alina1380 [7]

Answer:

Gravitational pull

Explanation:

There are four fundamental forces in nature:

- Gravitational force: it is an attractive force exerted between all objects having mass. Its magnitude is proportional to the product of the masses and inversely proportional to the square of the distance between the objects.

- Electromagnetic force: it is the force exerted between electrically charged object. It can be either attractive ore repulsive.  Its magnitude is proportional to the product of the charges and inversely proportional to the square of the distance between the objects.

- Strong nuclear force: it is the force responsible for holding protons and neutrons together in the nuclei of the atoms. It is attractive and acts only on a very short scale.

- Weak nuclear force: it is the force responsible for certain nuclear decay processes (radioactivity).

In this problem, landslides occur when certain masses of terrain are attracted towards the ground - they are attracted because of the gravitational force.

So, the correct answer is

gravitational pull

5 0
3 years ago
. A 13-g goldfinch has a speed of 8.5 m/s. What is its kinetic energy?
lesya692 [45]
PLEASE PRESS THE “Thanks!” BUTTON! :)
13 g —> 0.013 kg
KE = 1/2(m)(v)^2
KE = 1/2(0.013)(8.5)^2
KE = 0.47 J
3 0
2 years ago
Definition of artficial and natural radioactivity​
Genrish500 [490]
Search Results
Featured snippet from the web
The spontaneous emission of radiations from an unstable nuclei is known as natural radioactivity. on the other hand, The process of emission of radiations from naturally occurring isotopes when they are bombarded with sub-atomic particles or high levels of X-rays or gamma rays called artificial radioactivity.
8 0
2 years ago
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