Answer:
v_f =63 m/s
Explanation:
given,
starting force = 0 N
uniform rate increase to 36 N
time of action of Force = 35 s
mass of the body = 10 Kg
Speed of the object = ?
From the given data
if we plot F-t curve we will get a triangular shape
we know,
Impulse = Area between F-t curve
= (1/2) x base x height
= 0.5 x 35 x 36
= 630 N.s
now use Impulse-momentum theorem
Impulse = change in momentum
630 = 10 x (v_f - vi)
630 = 10 x (v_f - 0)
v_f =63 m/s
Speed of the object at 35 sec is equal to v_f =63 m/s
Answer:
a) 
b) 
c) 
d) 
Explanation:
Given:
- velocity of the sound from the source,

- original frequency of sound from the source,

- speed of the source,

(a)
We know time period is inverse of frequency:
Mathematically:



(b)
Distance travelled by the motorcycle during one period of sound oscillation:



(c)
The distance travelled by the sound during the period of one oscillation is its wavelength.



(d)
observer frequency with respect to a stationary observer:
<u>According to the Doppler's effect:</u>
...........................(1)
where:
are the observed frequency and the velocity of observer respectively.
Here, observer is stationary.

Now, putting values in eq. (1)


Answer:
B
Explanation:
there moving the waves through energy
Answer:
Spontaneous emission is a quantum effect, which in a semiclassical picture can be described as an emission which is stimulated by vacuum noise.