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3 years ago

1) A net force of 75.5 N is applied horizontally to slide a 225 kg crate across the floor.

Physics

1 answer:

dimulka [17.4K]3 years ago

7 0

Answer:

The acceleration of the crate is $0.3356\,\frac{m}{s^2}$

Explanation:

Recall the formula that relates force,mass and acceleration from newton's second law;

$F=m\,a$

Then in our case, we know the force applied and we know the mass of the crate, so we can solve for the acceleration as shown below:

$F=m\,a\\75.5\,N=225\,\,kg\,\,a\\a=\frac{75.5}{225} \,\frac{m}{s^2} \\a=0.3356\,\,\frac{m}{s^2}$

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A proton moves from a location where V = 87 V to a spot where V = -40 V. (a) What is the change in the proton's kinetic energy?

Art [367]

Answer: a) 127 eV; b) there is no change of kinetic energy.

Explanation: In order to explain this problem we have to use the change of potentail energy ( conservative field) is equal to changes in kinetic energy. So for the proton ther move to lower potential then they gain kinetic energy from the electric field. This means the electric force do work in this trayectory and then the protons increased changes its speed.

If we replace the proton by a electron we have a very different situaction, the electrons are located in a lower potental then they can not move to higher potential if any external force does work on the system.

In resumem, the electrons do not move from a point with V=87 to other point with V=-40 V. The electric force point to high potential so the electrons can not move to lower potential region (V=-40V).

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3 years ago

Finally, you are ready to answer the main question. Cheetahs, the fastest of the great cats, can reach 50.0 miles/hour in 2.22 s

muminat

Answer:

Acceleration = 10.06 m/s²

Explanation:

1 mile = 1.6093km

1609.3m = 1 mile

1 m = $\frac{1}{1609}$ mile

50.0 miles/hour = $\frac{50 * 1609.3}{60 * 60}$ m/s

= 22.35m/s

from equation

S = Ut + 1/2 at²

v = U + at

22.35 = 0 + a * 2.22

a = 22.35 ÷ 2.22

= 10.06 m/s²

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3 years ago

For a constant voltage, how is the resistance related to the current?

Aleksandr-060686 [28]

Answer:

Resistance is inversely proportional to current, so when the resistance doubles, the current is cut in half. Resistance is directly proportional to current, so when the resistance doubles, the current is cut in half.

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1 year ago

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

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3 years ago

The amount of oxygen in the reactants is 4 atoms. In the products, the oxygen is distributed to water (H2O) and O2 gas. Which co

Reil [10]

Answer:

2 in front of water and 1 in front of oxygen

Explanation:

This question is describing balancing a chemical reaction. A balanced chemical reaction has the same number of atoms of each elements on both the reactant and product side. According to the question, the reactants contains 4 atoms of oxygen. The reactants give rise to water (H20) and O2 in the products side.

This reaction is most likely the decomposition of hydrogen peroxide (H2O2) as follows:

H2O2 (l) ----> H2O (l) + O2(g)

Based on the description, H2O2 will be 2H2O2 as it is said to contain four atoms of oxygen. This means that, in order to have a balanced equation, we must place coefficient 2 in front of water and coefficient 1 in front of oxygen. That is;

2H2O2 (l) ----> 2H2O (l) + O2(g)

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3 years ago

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