The equation for Kinetic Energy is KE = 1/2 m v^2, where m is the mass, and v is the velocity. The velocity in this equation is squared, which means that it is exponential. That means that as the velocity increases, you will be multiplying by a bigger and bigger number! KE = 18 joules!
Explanation:
Given that,
Mass of a freight car, ![m_1=30,000-kg](https://tex.z-dn.net/?f=m_1%3D30%2C000-kg)
Speed of a freight car, ![u_1=0.85\ m/s](https://tex.z-dn.net/?f=u_1%3D0.85%5C%20m%2Fs)
Mass of a scrap metal, ![m_2=110,000\ kg](https://tex.z-dn.net/?f=m_2%3D110%2C000%5C%20kg)
(a) Let us assume that the final velocity of the loaded freight car is V. The momentum of the system will remain conserved as follows :
![30000\times 0.85=(30000+110000)V\\\\V=\dfrac{30000\times 0.85}{30000+110000}\\\\=0.182\ m/s](https://tex.z-dn.net/?f=30000%5Ctimes%200.85%3D%2830000%2B110000%29V%5C%5C%5C%5CV%3D%5Cdfrac%7B30000%5Ctimes%200.85%7D%7B30000%2B110000%7D%5C%5C%5C%5C%3D0.182%5C%20m%2Fs)
So, the final velocity of the loaded freight car is 0.182 m/s.
(b) Lost on kinetic energy = final kinetic energy - initial kinetic energy
![\Delta K=\dfrac{1}{2}[(m_1+m_2)V^2-m_1u_1^2)]\\\\=\dfrac{1}{2}\times [(30,000+110,000 )0.182^2-30000(0.85)^2]\\\\=-8518.82\ J](https://tex.z-dn.net/?f=%5CDelta%20K%3D%5Cdfrac%7B1%7D%7B2%7D%5B%28m_1%2Bm_2%29V%5E2-m_1u_1%5E2%29%5D%5C%5C%5C%5C%3D%5Cdfrac%7B1%7D%7B2%7D%5Ctimes%20%5B%2830%2C000%2B110%2C000%20%290.182%5E2-30000%280.85%29%5E2%5D%5C%5C%5C%5C%3D-8518.82%5C%20J)
Lost in kinetic energy is 8518.82. Negative sign shows loss.
Volume of gold in the phone = 10 cm^3
= 0.<span>00001 m^3 </span>
Density of gold = 19300 kg/m^3
1 kg mass = 2.2 pounds
Mass of 10 cm^3 of gold = 0<span>.00001 m^3 * (19300 kg/m^3)
= 0.193 kg
So
0.193 kg = 0.193 * 2.2 pounds
= 0.43 pounds
I think there is something wrong with the options given in the question.</span>
The magnitude of the sum of the frictional forces acting on the bike and its rider is 400N.
<h3>What is friction force?</h3>
The friction force is the opposing force which acts on the object which is in relative motion.
The driving force is equal and opposite to the friction force acting between road and bicycle.
Friction force = 400N
The friction force between rider and bike is zero.
So the magnitude of sum of friction force = 400N +0 = 400N
Thus, the magnitude of the sum of the frictional forces acting on the bike and its rider.
Learn more about friction force.
brainly.com/question/1714663
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The velocity of the submarine immediately after firing the missile is 0.0104 m/s
Explanation:
Mass of the submarine M=50 tonne=![50\times 1000=50000kg](https://tex.z-dn.net/?f=50%5Ctimes%201000%3D50000kg)
Mass of the missile m=40 kg
velocity of the missile v= 13m/s
we have to calculate the velocity of the submarine after firing
This is the recoil velocity and its expression is derived from the law of conservation of momentum
recoil velocity of the submarine
![V=-mv/M\\=-40\times 13/50000\\=0.0104 m/s](https://tex.z-dn.net/?f=V%3D-mv%2FM%5C%5C%3D-40%5Ctimes%2013%2F50000%5C%5C%3D0.0104%20m%2Fs)