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.
Answer:
The oven has many different heat sources from the bottom, sides, top, etc...
The microwave only has the sides.
Answer:
29.7 m/s fast, velocity is 29.7 m/s
Explanation:
Applying,
v² = u²+2gs...................... Equation 1
Where v = final velocity, u = initial velocity, g = acceleration due to gravity, s = distance.
Given: u = 0 m/s (dropped from height), s = 45 m
Constant: g = 9.8 m/s²
Substitute these values into equation 1
v² = 0²+2×9.8×45
v² = 882
v = √(882)
v = 29.7 m/s.
Hence the stone will be moving 29.7 m/s fast and the velocity is also 29.7 m/s