Sound source is at rest, you are moving with velocity v, f = frequency, c = speed of sound:
f = f0(1 + v/c)
115 = 100(1 + v/343)
115 = 100 + 100v/343
15 = 100v/343
v = 15*343/100
<span>
v = 51,45 m/s </span>
The answer is c you got to look for answers that make sense
Answer:
(A) Impulse = 9Ns
(B) F = 1286N
Explanation:
Impulse = change in momentum = m(v-u)
v = 0 (the hand comes to a stop)
u = -10m/s
Mass = 0.9kg
Impulse = 0.9 ×(0- (-10))
= 9Ns
(B) F×t = Impulse
F = Impulse/ t
t = 7ms = 7×10-³
F = 9/ (7×10-³)
F = 1286N.
Answer:
The gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.
the acceleration a = 7.8 m/s²
Explanation:
Given that :
the mass of the skydiver = 60 kg
Velocity = 50 m/s
Thus; gravitational force is definitely acting downwards towards the ground and this is equal to the weight of the skydiver.
Also; the air resistance is acting upward and the resultant of both forces = mass×acceleration
So;
mg-R = ma
60(9.8) - 120 = 60(a)
588 -120 = 60a
468 = 60a
a = 
a = 7.8 m/s²
Hence, the acceleration a = 7.8 m/s²