Answer:
37.42 m/s
Explanation:
We know that apparent frequency, is given by
where f is the given frequency in this case 392, V is the speed of sound in air which is given as 343 and is the speed of car which is unknown, \bar f is given as 440 Hz
u= 215 km/hr = 215 * 1000/ 3600 = aprx 60m/s
v=0
t=2.7sec
v= u - at
u= at
60/2.7 = 22.23 m/s^2
Hope it helps
It's a measure of the acceleration
Answer:
the speed of the satellite is 12,880.53 km/h
Explanation:
Given;
radius of the circular orbit, r = 24,600 km
time taken to revolve around Earth, t = 12 hours
The circumference of the satellite is calculated as;
L = 2πr
L = 2π x 24,600 km
L = 49,200π km
L = 154,566.36 km
The speed of the satellite;
v = L/t
v = 154,566.36 / 12
v = 12,880.53 km/h
Therefore, the speed of the satellite is 12,880.53 km/h
Answer: 430 nm
Explanation:
For 257 kJ to dislodge one mole of electrons we need,
275 x 10^3 / 6 x 10^23 = 4.6 x 10^-19
Using Einstein’s relationship between energy, frequency and wavelength
E = hf = h x (c/landa)
Therefore
Landa = h x (c/E) = 6.6 x 10^-34 x (3 x 10^8 / 4.6 x 10^-19 = 4.3 x 10-7 m.
In nm, landa = 430 nm