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.
Answer:
The law of conservation of energy can be seen in these everyday examples of energy transference: Water can produce electricity. Water falls from the sky, converting potential energy to kinetic energy.
The cue ball loses energy because the energy it had has been transferred to the 8 ball, so the cue ball slows down
Explanation:
Answer:
Explained below
Explanation:
1) Liquid in glass thermometer: This type of thermometer is used primarily to measure the temperatures from inspection of changes in volume of liquid.
Thermometry substance is mercury or alcohol
2) Gas thermometer: This type is used to measure temperature as a result of changes in gas pressure or volume.
Thermometry substance is Gas.
3) Resistance thermometer: This type is used to measure temperature due to changes in electric resistance.
Thermometry substance is Resistance wire.
4) Thermocouple thermometer: This type is used to measure the temperature due to changes in electrical potential difference occurring between two metal junctions.
Thermometry substance is two wires that are dissimilar.
5) Bimetallic thermometer: This is a type of thermometer that measures temperature by converting temperature into mechanical displacement by making use of Bimetallic strip.
Thermometry substance is two metals that are dissimilar.
Answer:
Option B
Explanation:
Speed of a wave is denoted by:
v=fλ
where f is the frequency which is unchanged 15Hz and λ is the new wavelength which is 28m
v=fλ
That’s the answer hope you enjoy
