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Luba_88 [7]
3 years ago
15

A 1200 kg car is travelling qt 20m\s determine the work that must be done on the car by the frictional force of the brakes to st

op the car
Physics
1 answer:
Anestetic [448]3 years ago
4 0

Answer:

240000 Joules

Explanation:

Applying,

The work that must be done by the frictional force of the brake to stop the car must be equal to the kinetic energy of the car.

W = mv²/2.................. Equation 1

Where W = work done by the frictional force of the brake, m = mass of the car, v = velocity of the car.

From the question,

Given: m = 1200 kg, v = 20 m/s

Substitute these values into equation 1

W = (1200×20²)/2

W = 240000 Joules

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(b) Find the position, velocity, and acceleration of the mass at time t = 5π/6.
Juli2301 [7.4K]
Solution 
x(t) = 8 cos t, x(5π/6)= 8 cos(<span>5π/6)
</span>cos(5π/6)=cos(3π/6 + 2π/6 )=cos(π/3 +π/2)= - sin π/3  (cos (x+<span>π/2)= -sinx)
</span>x(t) = -8sin <span>π/3 = - 4 .sqrt3
</span>v(t) = -8sint = -8sin (π/3 +<span>π/2)= -8 cosπ/3 </span>(sin (x+π/2)= cosx)
v(t) =<span> -8 cosπ/3 = -8/2= - 4 
</span>a(5π/6) = - 8cost = -(- sin π/3)= 4 .<span>sqrt3
</span>a(5π/6) =  4 .<span>sqrt3</span>
4 0
3 years ago
Which force is reasonable for making fusion possible in the sun?
andreev551 [17]

The force is reasonable for making fusion possible in the Sun is heat energy.

<h3>What is nuclear fission and fusion?</h3>

When the slow moving neutrons are bombarded with the heavy radioactive nuclei, the product is the more number of neutrons are produced with the large amount of energy. This multiplying process is called nuclear fusion.

The amount of energy produced in such a reaction can be calculated using the equivalence of mass and energy relationship.

E = mc²

The same happens in nuclear fusion where large amount of energy is needed to make more heavy nuclei.

Thus, fusion requires heat energy to continue the reaction.

Learn more about nuclear fusion and fission.

brainly.com/question/22991718

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8 0
2 years ago
Differences between freezing point and melting point (Atleast 5 differences)​
labwork [276]

Answer:

What is freezing point?

A liquid's freezing point is determined at which it turns into a solid. Corresponding to the melting point, the freezing point often rises with increasing pressure. In the case of combinations and for some organic substances, such as lipids, the freezing point is lower than the melting point. The first solid which develops when a combination freezes often differs in composition from the liquid, and the development of the solid alters the composition of the remaining liquid, typically lowering the freezing point gradually. Utilizing successive melting and freezing to gradually separate the components, this approach is used to purify mixtures.

What is melting point?

The temperature at which a purified substance's solid and liquid phases may coexist in equilibrium is referred to as the melting point. A solid's temperature goes up when heat is added to it until the melting point is achieved. The solid will then turn into a liquid with further heating without changing temperature. Additional heat will raise the temperature of the liquid once all of the solid has melted. It is possible to recognize pure compounds and elements by their distinctive melting temperature, which is a characteristic number.

The difference between freezing point and melting point:

  1. While a substance's melting point develops when it transforms from a solid to a liquid, a substance's freezing point happens when a liquid transforms into a solid when the heat from the substance is removed.
  2. When the temperature rises, the melting point can be seen, and when the temperature falls, the freezing point can be seen.
  3. When a solid reaches its melting point, its volume increases; meanwhile, when a liquid reaches its freezing point, its volume decreases.
  4. While a substance's freezing point is not thought of as a distinctive attribute, its melting point is.
  5. While external pressure is a significant component in freezing point, atmospheric pressure is a significant element in melting point.
  6. Heat must be supplied from an outside source in order to reach the melting point for such a state shift. When a material is at its freezing point, heat is needed to remove it from the substance in order to alter its condition.

<em>Reference: Berry, R. Stephen. "When the melting and freezing points are not the same." Scientific American 263.2 (1990): 68-75.</em>

7 0
2 years ago
What drives plate tectonics in the earths interior
xxTIMURxx [149]
The convection going on with the magma in the asthenosphere
4 0
3 years ago
Read 2 more answers
The Burj Khalifa is the tallest building in the world at 828 m. How much work would a man with a weight of 700 N do if he climbe
Hoochie [10]

Answer:

579600J

Explanation:

Given parameters:

Height of the building  = 828m

Weight of the man  = 700N

Unknown:

Work done by the man  = ?

Solution:

The work done by the man is the same as the potential energy expended.

 Work done:

             Work done  = Weight x height  = 700 x 828

        Work done  = 579600J

6 0
3 years ago
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