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Andrei [34K]
3 years ago
12

A car traveling at 45 km/h starts to brake, and comes to a stop over a distance of 18 m. Calculate the acceleration

Physics
1 answer:
lukranit [14]3 years ago
8 0

Answer:

Acceleration, a=8.68\ m/s^2

Explanation:

Given that,

Initial speed of a car, u = 45 km/h = 12.5 m/s

Final speed, v = 0 (as they comes to rest)

Distance, d = 18 m

We need to find the acceleration of the breaking car. Using third equation of motion as follows :

v^2-u^2=2ad\\\\\text{Where a is acceleration of the car}\\\\a=\dfrac{v^2-u^2}{d}\\\\a=\dfrac{(12.5)^2}{18}\\\\a=8.68\ m/s^2

So, the acceleration of the braking car is 8.68\ m/s^2.

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Which of the following statements is an accurate description of sound transmission through various mediums?
yaroslaw [1]

Answer: The accurate statement which describes the transmission of sound through various medium is D.

Explanation:

Sound is longitudinal wave in which the vibration of particles travels parallel to the propagation of the motion of the wave. It requires a medium to travel. It consists of compression and rarefaction.

Sound insulator prevents the sound to travel for example plastic, wood etc. Sound travels faster in solid medium than in liquid medium. Sound travels faster in liquid than in gas. Less elastic material absorbs sound for example paper in compare to inelastic material.

Therefore, the accurate statement which describes the transmission of sound through various medium is "Sound insulators prevent sound from being transmitted better than elastic solids.

3 0
3 years ago
Read 2 more answers
Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial p
Archy [21]

Based on all we know about the terrestrial worlds, the  single factor appears to play the most important role in a terrestrial planet's geological destiny is size size of terrestrial planet .

According to the question

Terrestrial Planets:

They belongs to a class of planets that are like the earth

Geological destiny :

Geology is biological destiny: Whatever minerals land or are deposited in a place determine what or who can make a living there millions of years later

Based on all we know about the terrestrial worlds, what single factor appears to play the most important role in a terrestrial planet's geological destiny

i.e

The size of terrestrial planet is one of the factors to play the most important role in a terrestrial planet's geological destiny  

which determines how long the planet can retain internal heat, which drives geological activity because  Smaller worlds cool off faster and harden earlier .

Hence, Based on all we know about the terrestrial worlds, the  single factor appears to play the most important role in a terrestrial planet's geological destiny is size size of terrestrial planet .

To know more about terrestrial here:

brainly.com/question/13490379

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6 0
2 years ago
Before beginning an experiment Mrs. Wilson warns her science class not to drop the bar magnets on the floor what is the most lik
Ainat [17]

Answer:

They could lose their magnetism if they are dropped too hard or banging against something (the ground)

Explanation:

the domains may bump out of alignment. hope this helps ! :)

7 0
3 years ago
A 20-gram bullet traveling at 250 m/s strikes a block of wood that weighs 2 kg. With what velocity will the block and bullet mov
Shkiper50 [21]

Answer:

the velocity of the bullet-wood system after the collision is 2.48 m/s

Explanation:

Given;

mass of the bullet, m₀ = 20 g = 0.02 kg

velocity of the bullet, v₀ = 250 m/s

mass of the wood, m₁ = 2 kg

velocity of the wood, v₁ = 0

Let the velocity of the bullet-wood system after collision = v

Apply the principle of conservation of linear momentum to calculate the final velocity of the system;

Initial momentum = final momentum

m₀v₀ + m₁v₁ = v(m₀ + m₁)

0.02 x 250  + 2 x 0    =    v(2  + 0.02)

5 + 0 = v(2.02)

5 = 2.02v

v = 5/2.02

v = 2.48 m/s

Therefore, the velocity of the bullet-wood system after the collision is 2.48 m/s

6 0
3 years ago
A helicopter descends from a height of 600 m with uniform negative acceleration, reaching the ground at rest in 5.00 minutes. de
uranmaximum [27]
Given:
h = 600 m, the height of descent
t = 5 min = 5*60 = 300 s, the time of descent.

Let a =  the acceleration of descent., m/s².
Let u =  initial velocity of descent, m/s.
Let t = time of descent, s.
The final velocity is v = 0 m/s because the helicopter comes to rest on the ground.
Note that u,  v, and a are measured as positive upward.

Then
 u + at = v
(u m/s) + (a m/s²)*(t s) = 0
u = - at
u = - 300a                  (1)

Also,
u*t + (1/2)at² = -h
(um/s)*(t s) + (1/2)(a m/s²)*(t s)² = 600
ut + (1/2)at² = 600       (2)
From (1), obtain
-300a +(1/2)(a)(90000) = -600
44700a = -600
a = - 1.3423 x 10⁻² m/s²

From (1), obtain
u = - 300*(-1.3423 x 10⁻²) = 4.03 m/s

Answer:
The acceleration is 0.0134 m/s² downward.
The initial velocity is 4.0 m/s upward.

3 0
3 years ago
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