Answer:
The correct answer is d
Explanation:
In this exercise they ask us which statement is correct, for this we plan the solution of the problem, this is a Doppler effect problem, it is the frequency change due to the relative speed between the emitter and the receiver of sound.
The expression for the Doppler effect of a moving source is
f ’= (v / (v- + v_s) f
From this expression we see that if the speed the sound source is different from zero feels a change in the frequency.
The correct answer is d
Falling from an airplane.
Answer:
Work done = -220,000 Joules.
Explanation:
<u>Given the following data;</u>
Mass = 1100kg
Initial velocity = 20m/s
To find workdone, we would calculate the kinetic energy possessed by the car.
Kinetic energy can be defined as an energy possessed by an object or body due to its motion.
Mathematically, kinetic energy is given by the formula;

Where,
- K.E represents kinetic energy measured in Joules.
- M represents mass measured in kilograms.
- V represents velocity measured in metres per seconds square.
Substituting into the equation, we have;
K.E = 220,000J
Therefore, the workdone to bring the car to rest would be -220,000 Joules because the braking force is working to oppose the motion of the car.