Answer:
False
Explanation:
Warmer air is less dense than cold, which is why warm air tends to rise and cold air sinks. Being acted on by gravity, colder, denser air weighs more and exerts greater pressure per unit area.
Explanation:
average speed is the total distance divided by total time
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:
Explanation:
Tension provides centripetal force in the circular motion . In circular motion work done by force = torque x angle
torque is zero as , centripetal force passes through axis of rotation that is center.
So work done by centripetal force = 0
So work done by tension on M = 0
