Consider a long train moving at speed v. Now consider a passenger throwing a ball inside this train, towards the back of the train, with same velocity v (but in the opposite direction of the train movement).
- A passenger inside the train will see the ball moving with speed v
- For an observer outside the train, however, the ball will appear as still. In fact, for him the ball will have a speed v (given by the movement of the train) -v (velocity of the ball but moving in the opposite direction), so the net velocity will be v+(-v)=0.
Answer: buzzer.
The working principle of a buzzer is the conversion of electrical energy to sound energy.
The switch just cuts or permits the flow of current, the motor convertes electrical or other kind of energy into mechanical energy, a bulb converts electrical energy into light and a battery converts chemical energy into electrical energy.
Answer:
Explanation:
Suppose when bucket is half full it has a mass of 2 m rotating in a circle of radius r
When Bucket is quarter full then it has a mass of m rotating in a circle of radius r.
When an object moves in a circular path then it experiences an inward force which is given by
where v=velocity of bucket
Force in case 2 is given by
Thus 
therefore force required in half bucket is more than force required in quarter bucket full.
Efficiency = 1000/2000 = 0.5 = 50%
Answer:
(h₁-h₂) = 2.30 10² m
Explanation:
The pressure depends on the height with the formula
P = P_atm + rho g h
Let's apply this expression for the building
P₁ = P_atm + rho_air g h₁
P₂ = P_atm + rho_air g h₂
Subtract
P₁ - P₂ = roh_air g (h₁ –h₂)
The measured pressure is in mm Hg to take this unit to units of pressure must be multiplied by the density of mercury and the acceleration of gravity
P₁- P₂ = rho_Hg g (h₁-h₂) _Hg
rho_Hg g (h₁-h₂) _Hg = roh_air g (h₁ –h₂)
(h₁ –h₂) = rho_Hg / rho_air (h₁-h₂) _ Hg
Let's calculate
(h₁-h₂) = 13600 / 1.18 (695-675)
(h₁-h₂) = 2.30 10⁵ mm
Let's reduce to meter
(h₁-h₂) = 2.30 10⁵ mm (1 m / 10³ mm)
(h₁-h₂) = 2.30 10² m
