Answer:
The frequency heard by the motorist is 4313.2 Hz.
Explanation:
let f1 be the frequency emited by the police car and f2 be the frequency heard by the motorist, let v1 be the speed of the police car and v2 be the speed of the motorist and v = 343 m/s be the speed of sound.
because the police car is moving towards the motorist at a higher speed, then the motorist will hear a increasing frequency and according to Dopper effect, that frequency is given by:
f1 = [(v + v2/(v - v1))]×(f2)
= [( 343 + 30)/(343 - 36)]×(3550)
= 4313.2 Hz
Therefore, the frequency heard by the motorist is 4313.2 Hz.
Answer:
The power of the pump is 337.5 W.
Explanation:
Power is the rate of transfer of energy or the rate at which work is done. It is measured in watts (W).
Power = 
But the energy here is the kinetic energy (K.E), which is the energy possessed by a moving body or object.
K.E =
m
where m is the mass = 90 kg and v is the velocity = 15 m/s.
K.E =
× 90 × 
= 10125 Joules
K.E = 10125 J = 10.125 KJ
So that the power of the pump when t = 30 s is;
Power = 
= 337.5 W
The power of the pump is 337.5 W.
Philosophy or any other synonym to the word philosophy <span />
Answer:
<h2>0.90cm</h2>
Explanation:
Hooke's law state that, provided the elastic limit of an elastic material is not exceeded, the extension e is directly proportional to the applied force.
given data
mass m= 3.5kg
extension e= 2.10cm to m = 2.1/100=0.021
let us solve for the spring constant k
we know that
F=ke--------Hooke's law
F=ma-------1st law of motion
ma=ke
k=ma/e
Assume a=10m/s^2
k=3.5*10/0.021
k=35/0.021
k=1666.66N/m
(a) If the 3.50-kg object is removed, how far will the spring stretch if a 1.50-kg block is hung on it
so mass is now= 1.5kg
we found k = 1666.66N/m
ma=ke
e=ma/k
e=1.5*10/1666.66
e=15/1666.66
e=0.009m
in cm =0.90cm
Answer: When quantities have the same relative size. In other words they have the same ratio corresponding in size or amount to something else.
Explanation: Example: "A rope's length and weight are in proportion."
Example: "The punishment should be proportional to the crime"