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pishuonlain [190]
3 years ago
11

A ball rolls onto the path of your car as you drive down a quiet neighborhood street. To avoid hitting the child that runs to re

trieve the ball, you apply your brakes for 1.05 s. The car slows down from 15.0 m/s to 9.00 m/s. The mass of the car is 1250 kg. (a) During the time the brakes were applied, what was the average force (in N) exerted on your car?
Physics
1 answer:
ehidna [41]3 years ago
7 0

Answer:

F = 7.143 kN

Explanation:

given,

time taken to apply break = 1.05 s

car slows down from 15 m/s to 9 m/s

mass of the car = 1250 Kg

force is equal to the change in momentum with respect to time.

F = \dfrac{\Delta P}{t}

F = \dfrac{m(v_f - v_i)}{t}

F = \dfrac{1250\times (9 - 15)}{1.05}

F = \dfrac{-7500}{1.05}

F = -7142.85 N

F = - 7.143 kN

Force is acting opposite direction of velocity of car i.e. the sign is negative.

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An electromagnetic wave is propagating towards the west. At a certain moment the direction of the magnetic field vector associat
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Answer:

either +z direction or -z direction.

Explanation:

The direction of the electric field, in an electromagnetic wave always is perpendicular to the direction of the magnetic field and the direction of propagation of the wave.

You assume a system of coordinates with the negative x axis as the west direction, and the y axis as the up direction

In this case, the wave is propagating toward the west (- x direction), and the magnetic field vector points up (+ y direction), then, it is mandatory that the electric field vector points either +z direction or -z direction.

5 0
3 years ago
What is an electron?<br><br><br> (it’s D lol)
kupik [55]

Answer:

D

Explanation:

4 0
3 years ago
Select the statements that correctly interpret the data in this heating curve.
tekilochka [14]

The consistent temperature indicated by section 2 represents the flow of energy lost as the water freezes.

Section 2 indicates that energy is being utilized to bring all molecules to the melting point.

Section 4 indicates that the temperature is stable until all molecules reach the boiling point.

The increasing temperature in section 5 indicates that molecular motion is increasing.

Explanation:

The figure is missing: find it in attachment.

The graph represents the temperature of a block of ice as heat is continuously supplied to it.

At the beginning (section 1), the temperature increases: in this phase, the heat supplied to the ice is used to increase the kinetic energy of vibration of the molecules of ice.

When the ice reach point A (melting point), the ice starts to melt. In this phase (section 2), the temperature of the substance remains constant, because all the heat supplied is used to break the bonds between the molecules, converting the ice into liquid water.

At point B, the ice has completely melted, and therefore we now have liquid water.

In sector 3 (between B and C), the temperature of the water increases again as we supply more and more heat: this heat, in fact, is used to increase the kinetic energy of the molecules, which move faster and faster.

Then, the water reaches the boiling point (point C): after that, the water starts to boil, (sector 4) and the heat supplied is entirely used to remove the intermolecular forces between the molecules of water; as a result, the temperature remains constant during the process.

At poind D, the water has completely boiled, and converted into gas state (steam).

After that, the temperature of the steam starts to increase again (sector 5) as more and more heat is supplied, because it is used to increase the kinetic energy of the molecules.

Therefore, the correct statements are:

The consistent temperature indicated by section 2 represents the flow of energy lost as the water freezes.

Section 2 indicates that energy is being utilized to bring all molecules to the melting point.

Section 4 indicates that the temperature is stable until all molecules reach the boiling point.

The increasing temperature in section 5 indicates that molecular motion is increasing.

3 0
3 years ago
Read 2 more answers
The modulus of elasticity for a ceramic material having 4.7 vol% porosity is 317 GPa. (a) Calculate the modulus of elasticity (i
elena-s [515]

Answer:

The answer is below

Explanation:

a) Given that the modulus of elasticity (E) = 317 GPa, to find the modulus of elasticity (in GPa) for the nonporous material (E_o), we use the formula:

E_0=\frac{E}{1-1.9P+0.9P^2}\\\\where\ P=4.7\%=0.047,hence:\\\\ E_0=\frac{317}{1-1.9(0.047)+0.9(0.047)^2}\\\\E_0=347.3\ GPa

b) If the porosity P = 11.1%, then the modulus of elasticity is:

E=E_0(1-1.9P+0.9P^2)=347.3(1-1.9(0.111)+0.9(0.111)^2)=278\ GPa

5 0
3 years ago
Which famous scientist is associated with the force of gravity?
jenyasd209 [6]

Answer:

Isaac Newton

Explanation:

Your welcome

7 0
3 years ago
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