I think shock waves require more speed they travel at the speed of sound
Answer:
<em>To reverse the direction of an electric current, we simply reverse the voltage either automatically with the help of some switching circuitry or manually by changing the voltage source terminals connection. </em>
Explanation:
For electric current to flow, there must be a potential difference, usually referred to as the voltage. The electric current flow is analogous to the flow of water under the action of a pump, through a series of pipe connections. The voltage is similar to the driving action of the pump, and current flows the same way water flows. The resistance due to drag on the pipe wall is equivalent to electric resistance. For current to flow in the reverse direction, the voltage or rather, the potential difference is changed, causing the current to flow in the opposite direction. This can be done by switching the terminals of the voltage source, or by automatic means. The automatic switching can be done with a transistor based circuitry.
Answer: Phillipe wins the race
Explanation:
Given
Length of track=20 m
Velocity of Phillippe=2 m/s w.r.t sidewalk
Velocity of sidewalk=1.5 m/s
Rena velocity=2 m/s
Therefore absolute velocity of P is 2+1.5=3.5 m/s
Time taken by phillippe 
=5.714+10=15.714 s
Time taken by rena

as the time taken by phillippe is less than rena therefore Phillippe wins the race.
Metals are giant structures of atoms held together by metallic bonds. “Giant” implies that large but variable numbers of Atoms are involved - depending on the size of the bits of metal. most metals are close packed - that is, they fit as many items as possible into the available volume.
Answer:
mass of box 1 = 2.20 kg
mass of box 2 = 5.93 kg
Explanation:
Let the mass of box 1 and box 2 is respectively
and 
so we will have
Force applied on box 1 then acceleration



Now we know that contact force between them in above case is given as



now we have
