Here in all such collision type question we can use momentum conservation as we can see that there is no external force on this system

as we know that




now from above equation we have



so the speed of combined system is 2 m/s
A. Energy is transmitted by all waves.
Pressure decreases with increasing altitude. The pressure at any level in the atmosphere may be interpreted as the total weight of the air above a unit area at any elevation. At higher elevations, there are fewer air molecules above a given surface than a similar surface at lower levels.
Answer:
Hey!
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Voltage (V) = 0.8V
Current (I) = 200 mA = 200/10^3 = 2/10
Resistance = ?
Resistance = Voltage / Current
Voltage = Current × Resistance
0.8 = 2/10 × Resistance
0.8×10/2 = Resistance
8/2 = Resistance
Resistance = 4 ohm
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Hope it helps...!!!
Explanation: