Answer:
A
Explanation:
paddling a canoe to make the boat move
Using the idea of motion under gravity, it will take 0.5 seconds more before the phone hits the ground.
<h3>What is the distance covered?</h3>
The distance covered is obtained form the equations of kinematics under gravity.
Now;
v = u + gt
Recall that it was dropped from a height hence u = 0 m/s
v = gt
v = 9.8 m/s^2 * 4 s
v = 39.2 m/s
Now;
h = ut + 1/2gt^2
but u = 0 m/s
h = 1/2gt^2
h = 1/2 * 9.8 * (4)^2
h = 78.4 m
The phone will not hit the ground within this time
For the phone to hit the ground;
h = 1/2gt^2
if h = 100 m
100 = 1/2 * 9.8 * t^2
2 * 100/9.8 = t^2
t = √2 * 100/9.8
t = 4.5 seconds
It will take about 0.5 seconds more before the phone will hit the ground.
Learn more about motion under gravity:brainly.com/question/15120445
#SPJ1
Answer:
C
Explanation:
Given that a liquid at rest in a fixed container exerts a force perpendicular to the wall of the container. Two students make claims about the microscopic cause of this force. Student A says that the force exerted by individual molecules as they bounce off the wall is always perpendicular to the wall. Student B says that the molecules may strike the wall at angles that are not perpendicular. Which student is correct and why?
The correct answer is option C
Student B . The molecules in a liquid are in random motion at the microscopic scale. For every atom that hits at an angle to one side of perpendicular, there is likely to be another atom hitting at the same speed at the same angle on the other side of perpendicular. On average the nonperpendicular components cancel
Answer:
-54 m/s²
Explanation:
Acceleration is defined as the change in velocity of a body with respect to time. Mathematically,
Acceleration A = change in velocity/time
A = dv/dt
Given Vx = at − bt³
The time at which the particle reaches its maximum displacement is at when vx = 0.
0 = at-bt³
t(a-bt²) = 0
a-bt² = 0
a = bt²
t² = a/b ... (1)
A = dvx/dt = a - 3bt²(by differentiating)
Acceleration = a - 3bt²... (2)
Substituting t² = a/b into equation 2 will give;
Acceleration = a - 3b(a/b)
Acceleration = a-3a
Acceleration = -2a
Substituting the value of a = 27m/s into the resulting equation of acceleration gives;
Acceleration = -2(27)
Acceleration = -54m/s²
Therefore at maximum displacement in the positive x direction, the acceleration of the particle will be -54m/s²
