Because the wall reflects sound waves to your ears bouncing off of the walls, even if it's in another room.
Answer:
a)
b) 
Explanation:
a) The displacement of the first object is 22.5 m, so we can use the next equation:



positive acceleration.
b) Using the same equation we can find the second value of the acceleration:


positive acceleration.
I hope it helps you!
Answer:
Explanation:
Considering non - relativistic approach : ----
Speed of electron = 1 % of speed of light
= .01 x 3 x 10⁸ m /s
= 3 x 10⁶ m /s
Kinetic energy of electron = 1/2 m v²
= .5 x 9.1 x 10⁻³¹ x ( 3 x 10⁶ )²
= 40.95 x 10⁻¹⁹ J
Kinetic energy in electron comes from lose of electrical energy equal to
Ve where V is potential difference under which electron is accelerated and e is electronic charge .
V x e = kinetic energy of electron
V x 1.6 x 10⁻¹⁹ = 40.95 x 10⁻¹⁹
V = 25.6 Volt .
Answer : The change in momentum of an object is equal to the impulse that acts on it.
Explanation :
Change in momentum : The change in momentum of an object is the product of the mass and the change in velocity of an object.
The formula of change in momentum is,

Impulse : An impulse of an object is the product of the force applied on an object and the change in time. Impulse is also equivalent to the change in momentum of an object.

Proof :

Hence, the change in momentum of an object is equal to the impulse that acts on it.
Answer:
3,150,000N
Explanation:
According to Newton's second law;
F = mass * acceleration
Given
Mass = 45000kg
acceleration = 70m/s^2
Substitute
F = 45000 * 70
F = 3,150,000N
Hence the force required to be produced by the rocket engines is 3,150,000N