Explanation:
Below is an attachment containing the solution.
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.
I think it's The fossil record. The same animal fossil is in Africa and South America. The animal could have not swim across so its the fossil record
F = G*((m sub 1*m sub 2)/r^2)
Answer:
the brightest found are Blue - White with
Explanation:
The energy emission of objects increases with their temperature, specifically Wien described the process in an expression
T = 2,898 10⁻³
With this expression we can find the temperature of the stars by the color they emit.
Specifically the Sun has a color of 550 nm which corresponds to 5400K
bright stars have a BLUE color corresponding to 7500K
the brightest found are Blue - White with a temperature of 20000K
