Answer:
b. v = 0, a = 9.8 m/s² down.
Explanation:
Hi there!
The acceleration of gravity is always directed to the ground (down) and, near the surface of the earth, has a constant value of 9.8 m/s². Since the answer "b" is the only option with an acceleration of 9.8 m/s² directed downwards, that would solve the exercise. But why is the velocity zero at the highest point?
Let´s take a look at the height function:
h(t) = h0 + v0 · t + 1/2 g · t²
Where
h0 = initial height
v0 = initial velocity
t = time
g = acceleration due to gravity
Notice that the function is a negative parabola if we consider downward as negative (in that case "g" would be negative). Then, the function has a maximum (the highest point) at the vertex of the parabola. At the maximum point, the slope of the tangent line to the function is zero, because the tangent line is horizontal at a maximum point. The slope of the tangent line to the function is the rate of change of height with respect to time, i.e, the velocity. Then, the velocity is zero at the maximum height.
Another way to see it (without calculus):
When the ball is going up, the velocity vector points up and the velocity is positive. After reaching the maximum height, the velocity vector points down and is negative (the ball starts to fall). At the maximum height, the velocity vector changed its direction from positive to negative, then at that point, the velocity vector has to be zero.
The answer should be 5 it’s easy
Answer:
E) 800 km/h
Explanation:
The computation of the average vector velocity module of the plane, at that time is shown below:
The displacement vector is
d^2 = d1^2 + d2^2
where,
d1 = northeast displacement
d2 = southeast displacement
Now
d^2 = (120)^2 + (160)^2
= 14400 + 2560
= 40000
= √40000
d = 200 km
Now the average velocity is
V = ΔS ÷ Δt
= 200 ÷ 1 ÷ 4
= 200 × 4
= 800 km/h
<u>Answer:</u> The correct statement is combining baking soda and vinegar will cause a chemical change.
<u>Explanation:</u>
A chemical reaction is defined as the reaction in which two or more chemical substances react to form two or more different chemical substances
A new substance (product) is formed in a chemical reaction when the bonds between the reactants are broken so that the new bonds between the products can be formed.
A physical process is defined as the process in which the physical state of matter takes place. Like, in the process of vaporization, a liquid state changes to the gaseous state without changing the composition of species.
When baking soda (Sodium bicarbonate) is reacted with vinegar (acetic acid), it leads to the formation of sodium acetate, water, and carbon dioxide.
A new compound is getting formed in this process which is denoted by the chemical equation:
Hence, the correct statement is combining baking soda and vinegar will cause a chemical change.
