Answer:
option D
Explanation:
given,
mass of the rifle,M = 2 Kg
mass of the bullet , m = 0.01 Kg
speed of the bullet, v = 200 m/s
recoil velocity ,v'= ?
initial velocity of bullet and rifle is zero.
using conservation of energy
Mu + m u' = M v'+ m v
0 + 0 = 2 x v' + 0.01 x 200
2 v' = -2
v' = -1 m/s
negative sign represent the velocity of rifle is in opposite direction of bullet.
hence, the correct answer is option D
9514 1404 393
Answer:
1.114 kg/m³
Explanation:
The total mass of the air in the balloon and the balloon + cargo will be the mass of the displaced air. If d is the density of the air in the balloon, then we have ...
2910d +308 = 2910×1.22
Solving for d, we find ...
2910d = 2919(1.22) -308
d = 1.22 -308/2910
d ≈ 1.114 . . . kg/m³
The density of the hot air is about 1.114 kg/m³.
Answer:
a) The car was moving at a speed of
b) The negative sign of denotes that the observer is coming towards the police car which is the source of the sound.
c)
Explanation:
Given:
- original frequency of the source,
- speed of the source,
- velocity of the obstacle car be,
- speed of sound,
- observed frequency,
<u>Using the equation from the Doppler's effect:</u>
a)
The car was moving at a speed of
b)
The negative sign of denotes that the observer is coming towards the police car which is the source of the sound.
c)
Now when,
Then,
Using the Doppler's eq.:
Answer:
yes
Explanation:
When all of the molecules (or atoms) in a system stop moving completely, that's as cold as they can get