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VARVARA [1.3K]
3 years ago
10

A car is moving with a constant velocity of 25 m/s. Which of the following is true?

Physics
1 answer:
S_A_V [24]3 years ago
6 0

b) the net force on the car is zero.

Explanation:

Let's analyze each option one by one:

a) the force from the engine is greater than all the forces of friction.  --> FALSE. In fact, the car is moving at constant velocity: this means that its acceleration is zero,

a = 0

and so Newton's second law becomes

\sum F = ma = 0

where \sum F is the net force on the car and m is its mass. This means that the net force on the car is zero: so, the force from the engine cannot be greater than all the forces of friction, otherwise the net force cannot be zero.

b) the net force on the car is zero.  --> TRUE, for what we said at point A)

c) the inertia is changing.  --> FALSE. The inertia of an object just depend on the mass and the velocity of the object: as neither the mass nor the velocity are changing in this problem, then the inertia of the car is not changing.

d) the forces of friction are proportional to the acceleration of the car.  --> FALSE. Generally, the force of friction acting on an object moving on a flat surface is

F_f = \mu mg

where \mu is the coefficient of friction, m is the mass, and g the acceleration of gravity. Therefore, the force of friction does not depend on the acceleration of the car.

e) All of the above. --> FALSE

Learn more about net force and Newton's second law:

brainly.com/question/3820012

#LearnwithBrainly

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The amount of space between two points is measure in unit?
Andreas93 [3]

Answer:

meters

Explanation:

I'm not positive if this is correct, your teacher may be looking for a broader answer so possibly just 'distance'. Hope this helps! <3

3 0
3 years ago
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How do hydrogen bonds affect boiling points?
Yuri [45]

Boiling points are raised by hydrogen bonds because they make different molecules desire to "attach" to one another, which requires more energy to do so. In water, for instance, the hydrogen proton is in a state that resembles ionization because the connections between oxygen and hydrogen, while covalent, are strongly polar. The oxygen also receives a partial negative charge. Therefore, hydrogen bonds are formed when the electro-positive H in one molecule is strongly electrostatically attracted to the electro-negative O in nearby molecules. Despite being weak links, they are powerful enough to significantly alter the liquid's characteristics.  

Thanks!

>> ROR

8 0
2 years ago
Which of the following is a hypothesis?
inna [77]

Answer:

C

Explanation:

Hypothesis is one of the science methods. Hypothesis is the same as guessing. It's a scientific method that precedes observations.

According to the question asking that Which of the following is a hypothesis ?

The correct option is C which is

If a squid is attacked by a predator, it will squirt ink

It is an hypothesis because there is no experimental evidence to back it up.

5 0
3 years ago
If the primary of a transformer were connected to a dc power source,
QveST [7]

Answer:

D. only briefly while being connected or disconnected.

Explanation:

As we know that transformer works on the principle of mutual inductance

here we know that as per the principle of mutual inductance when flux linked with the primary coil charges then it will induce EMF in secondary coil

So here when AC source is connected with primary coil then it will give output across secondary coil because AC source will have change in flux with time.

Now when we connect DC source across primary coil then it will not induce any EMF across secondary coil because DC source is a constant voltage source in which flux will remain constant always

So here in DC source the EMF will only induce at the time of connection or disconnection when flux will change in it while rest of the time it will give ZERO output

so correct answer will be

D. only briefly while being connected or disconnected.

8 0
3 years ago
A mass of 0.54 kg attached to a vertical spring stretches the spring 36 cm from its original equilibrium position. The accelerat
UNO [17]
<h2>Spring constant is 14.72 N/m</h2>

Explanation:

We have for a spring

            Force =  Spring constant x Elongation

            F = kx

Here force is weight of mass

           F = W = mg = 0.54 x 9.81 = 5.3 N

Elongation, x  = 36 cm = 0.36 m

Substituting

           F = kx

           5.3 = k x 0.36

             k = 14.72 N/m

Spring constant is 14.72 N/m

6 0
2 years ago
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