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4 years ago

Which car has the most kinetic energy?

Physics

1 answer:

mixas84 [53]4 years ago

5 0

Answer:

B. A car of mass 2000 kg with speed 7 m/s

Explanation:

The kinetic energy of an object is given by:

$K=\frac{1}{2}mv^2$

where m is the mass of the object and v is its speed.

From the formula, we see that the larger the mass and the speed of the object, the larger its kinetic energy. Among the choices given, we see that the car with largest mass and largest speed is car B, which has a mass of 2000 kg and speed of 7 m/s. Its kinetic energy is:

$K=\frac{1}{2}(2000 kg)(7 m/s)^2=49,000 J$

We can verify that the other cars have smaller kinetic energy. In fact:

- Car A: $K=\frac{1}{2}(1000 kg)(3 m/s)^2=4,500 J$

- Car C: $K=\frac{1}{2}(1000 kg)(7 m/s)^2=24,500 J$

- Car D: $K=\frac{1}{2}(2000 kg)(3 m/s)^2=9,000 J$

So, car B is the one which has most kinetic energy.

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The variables for Part II of this experiment include the force applied to the car and the acceleration of the car. Use the drop-

gregori [183]

Answer:

Independent variable: Force applied to the car

Dependent variable: The acceleration of the car

Explanation:

A scientific experiment involves three variables which are classified mainly as independent, dependent and constant variables.

The independent variable is the variable which can be changed or changes itself like weather, natural conditions and in a given question, the applied force on the car is considered.

The dependent variable is the variable which depends on the independent variable that is the force applied on the car. Therefore, the acceleration of the car can be considered as a dependent variable as it changes according to the applied force.

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3 years ago

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Which of the following is an example of electrical energy being converted to chemical energy?

tekilochka [14]

Answer : The correct option is, (B)

Explanation :

Electrical energy : It is defined as the movement of the electrons thought the wire.

Chemical energy : It is a type of energy which is stored in the bonds of a chemical compounds. During the chemical reaction, chemical energy is released in the form of heat.

Sound energy : It is a type of energy which is produced when an object vibrate.

Mechanical energy : It is a type of energy that can be used to do work.

The option A is incorrect because in this process, electrical energy being converted to the sound energy.

The option B is correct because in this process, electrical energy being converted to chemical energy. An oxidation-reduction reaction occurs in the storage battery.

The option C is incorrect because in this process, mechanical energy being converted to mechanical energy.

Hence, the option (B) A storage battery is charged using an electric current is an example of electrical energy being converted to chemical energy.

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4 years ago

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The waters of a lake will be most layered in which season

Mashcka [7]

Answer:

B. Spring

Explanation:

The waters of a lake will be the most layered in the spring because of the melting of the ice (which is just frozen water) and the direct heat going into the lake causing the warm water to rise up and the colder water to move further down, which creates even more layers.

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3 years ago

The magnitude of the magnetic field B a distance r from a long straight wire is B = μ 0 I 2 π r where μ 0 is the permeability co

PSYCHO15rus [73]

Answer:

The magnetic field is lowest for largest distance and highest when distance is least.

Explanation:

The magnitude of magnetic field strength at a distance 'r' from a long straight wire carrying current 'I' is given as:

$B=\frac{\mu_0 I}{2\pi r}\\Where,\mu_0\to permeability\ constant\ of\ free\ space$

Now, as per question, the distance 'r' is varied while keeping the current constant in the wire.

As seen from the above formula, the magnitude of magnetic field strength for a constant current varies inversely with the distance 'r'. This means that, as the value of 'r' increases, the magnitude of magnetic field strength decreases and vice-versa.

Therefore, the magnitude of magnetic field strength is maximum when the distance 'r' is least and the magnetic field is minimum for the largest distance.

Example:

If $B_1, B_2,\ and\ B_3$ are the magnitudes of magnetic field strengths for distances $r_1,r_2, \ and\ r_3$ respectively such that $r_1$ . Now, as per the explanation above, the order of magnitudes of magnetic field strength is:

$B_1>B_2>B_3$

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4 years ago

If a car is taveling with a speed 6 and comes to a curve in a flat road with radius ???? 13.5 m, what is the minumum value the c

Lemur [1.5K]

Answer:

$\mu_s \geq 0.27$

Explanation:

The centripetal force acting on the car must be equal to mv²/R, where m is the mass of the car, v its speed and R the radius of the curve. Since the only force acting on the car that is in the direction of the center of the circle is the frictional force, we have by the Newton's Second Law:

$f_s=\frac{mv^{2}}{R}$

But we know that:

$f_s\leq \mu_s N$

And the normal force is given by the sum of the forces in the vertical direction:

$N-mg=0 \implies N=mg$

Finally, we have:

$f_s=\frac{mv^{2}}{R} \leq \mu_s mg\\\\\implies \mu_s\geq \frac{v^{2}}{gR} \\\\\mu_s\geq \frac{(6\frac{m}{s}) ^{2}}{(9.8\frac{m}{s^{2}})(13.5m) }\\\\\mu_s\geq0.27$

So, the minimum value for the coefficient of friction is 0.27.

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3 years ago