Answer:
the pressure due to the water on the diver is 200,000 pascal
pressure = height × density × acceleration due to gravity
p = 20×1000×10
p=200,000 pascal
When acceleration is constant, the average velocity is given by
where 
and 
are the final and initial velocities, respectively. By definition, we also have that the average velocity is given by
where 
are the final/initial displacements, and 
are the final/initial times, respectively.
Take the car's starting position to be at 
. Then
So we have
You also could have first found the acceleration using the equation
then solve for 
via
but that would have involved a bit more work, and it turns out we didn't need to know the precise value of 
anyway.
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:
t = 5 s
Explanation:
Data:
- Initial Velocity (Vo) = 7 m/s
- Acceleration (a) = 3 m/s²
- Final Velocity (Vf) = 22 m/s
- Time (t) = ?
Use formula:
Replace:
Solve the subtraction of the numerator:
It divides:
How much time did it take the car to reach this final velocity?
It took a time of <u>5 seconds.</u>
