Answer:
The car stops in 7.78s and does not spare the child.
Explanation:
In order to know if the car stops before the distance to the child, you take into account the following equation:
(1)
vo: initial speed of the car = 45km/h
a: deceleration of the car = 2 m/s^2
t: time
xo: initial distance to the child = 25m
x: final distance to the child = 0m
It is necessary that the solution of the equation (1) for time t are real.
You first convert the initial speed to m/s, then replace the values of the parameters and solve the quadratic polynomial for t:


You take the first value t1 because it has physical meaning.
The solution for t is real, then, the car stops in 7.78s and does not spare the child.
I would say the plastic grip because glass, wood, and plastic are all good conductors of electricity
Answer:
Newton's Second Law of Motion says that acceleration (gaining speed) happens when a force acts on a mass (object). Riding your bicycle is a good example of this law of motion at work. Your bicycle is the mass. Your leg muscles pushing pushing on the pedals of your bicycle is the force.
Explanation:
-- "Free fall" means no forces acting on the object except for gravity.
-- An object dropped through air has two forces on it -- gravity and air resistance.
-- So we're looking for the part of the drop where air resistance is smallest.
-- The force of air resistance depends on the speed through the air, so the
force of air resistance is smallest when <em>velocity downward is smallest</em>.