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NeX [460]
3 years ago
11

A car that increases it's speed from 20 km/h to 100 km/h undergoes

Physics
1 answer:
enot [183]3 years ago
3 0
If a car increases its speed from 20km/h to 100 km/h undergoes positive acceleration. Hope this helped!
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How did the transcontinental railroad impact travel?
enot [183]

Answer:

D

Explanation:

The transcontinental railroad was worked on from both sides of America. At the Pacific Ocean and the Atlantic Ocean. The purpose was to make travel easier from one side of the country to the other, and to get American items to the east and west of America for export to other countries, as well as a few other reasons such as building up the interior of America.

5 0
3 years ago
A 0.01-kg object is initially sliding at 9.0 m/s. It goes up a ramp (increasing its elevation by 1.5 m), and then moves horizont
barxatty [35]

Answer:

During this motion, 0.133 J of heat energy was created

Explanation:

Hi there!

Let´s calculate the energy of the object in each phase of the motion.

At first, the object has only kinetic energy (KE):

KE = 1/2 · m · v²

Where:

m = mass of the object.

v = velocity.

KE = 1/2 · 0.01 kg · (9 m/s)²

KE = 0.405 J

When the object goes up the ramp, it gains some gravitational potential energy (PE). Due to the conservation of energy, the object must convert some of its kinetic energy to obtain potential energy. By calculating the potential energy that the object acquires, we can know the loss of kinetic energy:

PE = m · g · h

Where:

m = mass of the object.

g = acceleration due to gravity (9.81 m/s²)

h = height.

PE = 0.01 kg · 9.81 m/s² · 1.5 m

PE = 0.147 J

The object "gives up" 0.147 J of kinetic energy to be converted into potential energy.

Then, after going up the ramp, the kinetic energy of the object will be:

0.405 J - 0.147 J = 0.258 J

When the object reaches the spring, kinetic energy is used to compress the spring and the object obtains elastic potential energy (EPE). Let´s calculate the EPE obtained by the object:

EPE = 1/2 · k · x²

Where:

k = spring constant.

x = compression of the spring

EPE = 1/2 · 100 N/m · (0.05 m)² = 0.125 J

Then, only 0.125 J of kinetic energy was converted into elastic potential energy. The object is at rest at the end of the motion, i.e., the object does not have kinetic energy when it compresses the spring by 5.0 cm. Since energy can´t be lost, the rest of the kinetic energy, that was not used to compress the spring, had to be converted into heat energy:

Heat energy = initial kinetic energy - obtained elastic potential energy

Heat energy = 0.258 J - 0.125 J = 0.133 J

During this motion, 0.133 J of heat energy was created.

7 0
3 years ago
In the author's opinion, why is attitude the most important fitness level factor to consider? (
Cerrena [4.2K]
That's up to you because you have to go through the book to see their expressions
5 0
4 years ago
When the daughter nucleus produced in a radioactive decay is itself unstable, it will eventually decay and form its own daughter
Dmitrij [34]

Answer:

4.981 MeV

Explanation:

The quantity of energy Q can be calculated using the formula

Q = (mass before - mass after) × c²

Atomic Mass of thorium = 232.038054 u, atomic of Radium = 228.0301069 u and mass of Helium = 4.00260. The difference of atomic number and atomic mass  between the thorium and radium ( 232 - 228)  and ( 90 - 88)  show α particle was emitted.

1 u = 931.494 Mev/c²

Q = (mass before - mass after) × c²

Q = ( mass of thorium - ( mass of Radium + mass of Helium ) )× c²

Q = 232.038054 u - ( 228.0301069 + 4.00260) × c²

Q = 0.0053471 u × c²

replace 1 u = 931.494 MeV/ c²

Q = 0.0053471 × c² × (931.494 MeV / c²)

cancel c²  from the equation

Q = 0.0053471 × 931.494 MeV = 4.981 MeV

3 0
3 years ago
The boy on the tower throws a ball 20m downrange. What is his pitching speed?
san4es73 [151]

Answer:

The pitching speed of the ball is 19.7 m/s

Explanation:

  • Here, we can use the third equation of motion,  v^{2} = u^{2} - 2as
  • whereas v represents the final velocity, u represents initial velocity, a is the acceleration due to gravity and s is the displacement or distance an object traveled
  • Here, the initial velocity of the the ball is given as  zero and the acceleration due to gravity is 9.8  , the distance 's' is given as 20 m
  • Using the equation,  v^{2} = 2 * 9.8 * 20 = 392\\v = \sqrt{392} = 19.7m/s
  • Hence, the pitching speed of the ball is 19.7 m/s

5 0
3 years ago
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