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Sveta_85 [38]
3 years ago
13

At an accident scene on a level road, investigators measure a car's skid mark to be 93 m long. It was a rainy day and the coeffi

cient of friction was estimated to be 0.35. Use these data to determine the speed of the car when the driver slammed on (and locked) the brakes. Express your answer to two significant figures and include the appropriate units
Physics
1 answer:
USPshnik [31]3 years ago
6 0

Answer:

u = 25 m/s

Explanation:

given,                                

length of skid = 93 m          

coefficient of friction = 0.35

final velocity = 0 m/s              

initial velocity = ?                        

force here is friction  f = μ mg

F = ma                                                

now com paring                      

-μ mg = m a                      

a = - μ g                    

a = - 0.35 x 9.8              

a = -3.43 m/s²

we know,              

v² = u² + 2 a s                        

0 = u² - 2 x 3.43 x 93                

u² = 637.98                    

u = 25.26 m/s                      

u = 25 m/s (two significant figure)

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Answer:

To calculate the tension on a rope holding 1 object, multiply the mass and gravitational acceleration of the object. If the object is experiencing any other acceleration, multiply that acceleration by the mass and add it to your first total.

Explanation:

The tension in a given strand of string or rope is a result of the forces pulling on the rope from either end. As a reminder, force = mass × acceleration. Assuming the rope is stretched tightly, any change in acceleration or mass in objects the rope is supporting will cause a change in tension in the rope. Don't forget the constant acceleration due to gravity - even if a system is at rest, its components are subject to this force. We can think of a tension in a given rope as T = (m × g) + (m × a), where "g" is the acceleration due to gravity of any objects the rope is supporting and "a" is any other acceleration on any objects the rope is supporting.[2]

For the purposes of most physics problems, we assume ideal strings - in other words, that our rope, cable, etc. is thin, massless, and can't be stretched or broken.

As an example, let's consider a system where a weight hangs from a wooden beam via a single rope (see picture). Neither the weight nor the rope are moving - the entire system is at rest. Because of this, we know that, for the weight to be held in equilibrium, the tension force must equal the force of gravity on the weight. In other words, Tension (Ft) = Force of gravity (Fg) = m × g.

Assuming a 10 kg weight, then, the tension force is 10 kg × 9.8 m/s2 = 98 Newtons.

7 0
3 years ago
Why do covalent and ionic bonds form?
nevsk [136]

Answer:

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Explanation:

hope this helps!

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A box is at rest on a table. What can you say about the forces acting on the box?
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You can tell a lot about an object that's not moving,
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==> Since it is not accelerating, I can say that the forces on it are balanced.

==> That means that the sum of all forces acting on the box is zero,
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==> This in turn means that all of the horizontal forces are balanced,
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All of the forces on this list must add up to zero. So ...

(sliding friction force) = (pushing force), in the opposite direction.

If nobody pushing the box, then sliding friction force = zero.

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6 0
3 years ago
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aleksklad [387]

Answer:

about 229 feet.

Explanation:

According to my research on the information provided by the drivers educational book, It is said that a motor vehicle with good brakes that is going at 50 miles per hour can be stopped within about 229 feet. This is dependent 100% on having good brakes as well as there being normal driving conditions (on pavement with no rain or other weather that may affect driving conditions).

I hope this answered your question. If you have any more questions feel free to ask away at Brainly.

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