Answer:
The speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.
Explanation:
Given that, a child threw a stone straight down off a high bridge.
Initial velocity of the stone, u = 15 m/s
We need to find the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant. When it come down, it is moving under the action of gravity. Using equation of motion as :

So, the speed of the stone before it hit the river 3.00 sec later. Let v is the velocity at that instant is 45 m/s.
Answer:
The total current supplied by the source of voltage = 10.29 A
Explanation:
We have a 14-Ω coffee maker and a 14-Ω frying pan are connected in series.
Effective resistance = 14 + 14 = 28Ω
Now we have 28Ω and 20Ω in parallel
Effective resistance

So we have resistor with 11.67Ω in a 120 V source of voltage.
We have equation V = IR
Substituting
120 = I x 11.67
I = 10.29 A
The total current supplied by the source of voltage = 10.29 A
Answer:
Explanation:
b ) The problem is based on Doppler's effect of sound
f = f₀ x (V - v₀) /(
)
f is apparent frequency ,f₀ is real frequency , V is velocity of sound , v₀ is velocity of observer going away ,
is velocity of source going away
778 = 840 x (340 - 14)/ (340 +
)
340 +
= 341.18
= 1.18 m /s
it will go away from the observer or the cyclist.
speed of train = 1.18 m /s
a )
For a stationary observer v₀ = 0
f = f₀ x V /(
)
= 840 x 340 / (340 + 1.180)
= 837 Hz
Answer:
There are three types of material as per the condition of charge flow
1) Conductor
2) Insulator
3) Semiconductor
1) Conductors
As we know that conductors are those which offer very small resistance to the flow of charge
Resistivity of the conductors are very small
2) Insulators
These type of materials offer large resistance to the flow of charges and it will not pass the current through it
So resistivity of the insulators are large as compared to conductors
Answer:
KE = KE (incidental) - KE of emitted photons
or KE = h * f - Wf
So h * f = KE + Wf = 1.2 + 1.88 = 3.08 incident energy
If you double the frequency then h * f = 6.16
KE = 6.16 - 1.2 = 4.96 eV