This is a concrete example of the Doppler effect. This effect is the change of frequency experienced by the listener or the observer with respect to their relative distance to the source of the sound. There can be two equations to be applied: to the approaching source, and to the receding source.
Approaching source:
frequency observed = [v/(v-v,source)]*frequency of source, where v is the velocity of sound . Substituting,
1000 = [340/(340-v,source)]*frequency of source <---- equation 1
Receding source:
frequency observed = [v/(v+v,source)]*frequency of source, where v is the velocity of sound . Substituting,
800 = [340/(340+v,source)]*frequency of source <---- equation 2
Rearranging equation 1: [1000(340-v,source)]/340 = frequency of source
Equation 2: 800 = [340/(340+v,source)]*frequency of source
Substituting equation 1 to equation 2:
800 = [340/(340+v,source)]*[1000(340-v,source)]/340
Solving using the scientific calculator under shift-solve feature,
v,source = 37.78 m/s
Therefore, the train is moving at 37.78 m/s.
Answer:
yes the answer is C. 32.16
Answer: time t = 2 seconds
Explanation:
Given that
Power P = 50W
Energy E = 100J
How long did it take to move the box from the floor to the shelf ? This implies time taken.
Power is defined as the rate at which work is done. I.e
P = W.D/t
Where work done = energy
50 = 100/t
Make t the subject of formula
t = 100/50
t = 2 second
Answer:
104 kWh
Explanation:
To calculate the kWh you multiply power with the amount of hours.
So for this we take 5200 W × 20 = 104 000 Wh
Then change Wh to kWh so that makes 104 kWh
41kg object that is moving east at 5 m s