Answer:
The unbalanced force that caused the ball to stop was friction
Explanation:
As Newton's second law states, the acceleration of an object is proportional to the net force applied on the object:

therefore, in order to move at constant speed, an object should have a net force of zero (balanced forces) acting on it.
In this case, the ball slows down and eventually comes to a stop: it means that the ball is decelerating, so there are unbalanced forces (net force different from zero) acting on it. The unbalanced force acting on the ball is the friction: friction is a force against the motion of the object, which is due to the contact between the surface of the ball and the surface of the street, and this force is responsible for slowing down the ball.
Answer:
A. The sound wave will reflect off Buildings and automobiles.
Explanation:
This is because the sound waves would more likely propagate through diffraction through buildings and transmission through the air. It is also more likely to be absorbed by buildings than for multiple reflections to occur off buildings and automobiles. In the process of reflection, these materials would absorb the sound energy thereby reducing its ability to reflect.
Answer:
Explanation:
Given
mass of spring 
extension in spring 
downward velocity 
Position in undamped free vibration is given by

where 
also 



it is given


substituting values we get







Answer:
6.1 × 10^9 Nm-1
Explanation:
The electric field is given by
E= Kq/d^2
Where;
K= Coulombs constant = 9.0 × 10^9 C
q = magnitude of charge = 1.62×10−6 C
d = distance of separation = 1.53 mm = 1.55 × 10^-3 m
E= 9.0 × 10^9 × 1.62×10−6/(1.55 × 10^-3 )^2
E= 14.58 × 10^3/2.4 × 10^-6
E= 6.1 × 10^9 Nm-1
Answer:
I think it has to do something with their ionizations... not entirely sure though.
Explanation: