Answer:
D).happens when soil is weakened by water and seismic waves
Explanation:
Liquefaction is a phenomenon in which the strength of the soil weakens due to the earthquake or any other load. The solid behaves like a liquid. Liquefaction of soil below structures cause lot of damage during Earthquakes.The soil looses stiffness due to seismic waves and water.
Thus, the correct option is D.
FOUR USES OF CONCAVE MIRROR:Satellite dishes,headlights of a car, telescopes used for astronomical studies, and shaving mirrors because of there curved and reflective surface.
FIVE USES OF LENSES: Camera lens ,microscopes ,magnifying glass,eyeglasses,projector
Answer:
2.57 seconds
Explanation:
The motion of the ball on the two axis is;
x(t) = Vo Cos θt
y(t) = h + Vo sin θt - 1/2gt²
Where; h is the initial height from which the ball was thrown.
Vo is the initial speed of the ball, 22 m/s , θ is the angle, 35° and g is the gravitational acceleration, 9.81 m/s²
We want to find the time t at which y(t) = h
Therefore;
y(t) = h + Vo sin θt - 1/2gt²
Whose solutions are, t = 0, at the beginning of the motion, and
t = 2 Vo sinθ/g
= (2 × 22 × sin 35°)/9.81
= 2.57 seconds
Answer:
The acceleration of the object is 9.3 m/s²
Explanation:
For a straight movement with constant acceleration, this equation for the position applies:
x = x0 + v0 t + 1/2 a t²
where
x = position at time t
x0 = initial position
v0 = initial velocity
a = acceleration
t = time
we have two positions: one at time t = 1 s and one at time t = 2 s. We know that the difference between these positions is 14.0 m. These are the equations we can use to obtain the acceleration:
x₁ = x0 + v0 t + 1/2 a (1 s)²
x₂ = x0 + v0 t + 1/2 a (2 s)²
x₂ - x₁ = 14 m
we know that the object starts from rest, so v0 = 0
substracting both equations of position we will get:
x₂ - x₁ = 14
x0 + v0 t + 1/2 a (2 s)² - (x0 + v0 t + 1/2 a (1 s)²) = 14 m
x0 + v0 t + 2 a s² - x0 -v0 t - 1/2 a s² = 14 m
2 a s² - 1/2 a s² = 14 m
3/2 a s² = 14 m
a = 14 m / (3/2 s²) = <u>9.3 m/s² </u>
