Answer:
The sound intensity of train is 1000 times greater than that of the library.
Explanation:
We have expression for sound intensity level,
A train whistle has a sound intensity level of 70 dB
We have
A library has a sound intensity level of about 40 dB
We also have
Dividing both equations
The sound intensity of train is 1000 times greater than that of the library.
Answer:
A) 10 m/s
Explanation:
We know that according to conservation of momentum,
m1v1 + m2v2 = m1u1 + m2u2 ..............(equation 1)
where m1 and m2 are masses of two bodies, v1 and v2 are initial velocity before collision and u1 and u2 are final velocities after collision respectively.
From the given data
If truck and car are two bodies
truck : m1 = 2000 Kg v1 = 5 m/s u1 = 0
car : m2 = 1000 kg v2 = 0 u2 = ?
final velocity of truck and initial velocity of car are static because the objects were at rest in the respective time.
substituting the values in equation 1, we get
(2000 x 5) + 0 = 0 + (1000 x u2)
u2 = x 5
= 10 m/s
Hence after collision, car moves at a velocity of 10 m/s
Answer:
15.6m/s
Explanation:
V1= because the derivate of the position is the velocity
V1=12t+3
V2=20+-8t because the integral of the acceleration is the velocity
V2=
V1=V2 to see when the velocities of particles match
12t+3=20-4t^2
4t^2+12t-17=0 we resolve this with
and we take the positif root
t=1.05 sec
if we evaluate the velocity (V1 or V2) the result is 15.6m/s