Answer:
j
Explanation:
x = 4 t^2 - 2 t - 4.5
Position at t = 3 s
x = 4 (3)^2 - 2 (3) - 4.5 = 25.5 m
Velocity at t = 3 s
v = dx / dt = 8 t - 2
v ( t = 3 s) = 8 x 3 - 2 = 22 m/s
Acceleration at t = 3 s
a = dv / dt = 8
a ( t = 3 s ) = 8 m/s^2
When is the velocity = 0
v = 0
8 t - 2 = 0
t = 0.25 second
When is the position = 0
x = 0
4 t^2 - 2 t - 4.5 = 0

t = 1.4 second
Answer:
Intensity of beam 18 feet below the surface is about 0.02%
Explanation:
Using Lambert's law
Let dI / dt = kI, where k is a proportionality constant, I is intensity of incident light and t is thickness of the medium
then dI / I = kdt
taking log,
ln(I) = kt + ln C
I = Ce^kt
t=0=>I=I(0)=>C=I(0)
I = I(0)e^kt
t=3 & I=0.25I(0)=>0.25=e^3k
k = ln(0.25)/3
k = -1.386/3
k = -0.4621
I = I(0)e^(-0.4621t)
I(18) = I(0)e^(-0.4621*18)
I(18) = 0.00024413I(0)
Intensity of beam 18 feet below the surface is about 0.2%
The kinetic energy of this block-spring when the block has a speed (v) is given by K.E = 1/2 × (M + m/3)v².
<h3>What is kinetic energy?</h3>
Kinetic energy can be defined as a form of energy that is possessed by a person due to its motion or change in speed (acceleration).
<h3>How to calculate kinetic energy?</h3>
Mathematically, kinetic energy can be calculated by using this formula:
K.E = 1/2 × mv²
Where:
- K.E represents the kinetic energy.
- v represents the speed or velocity.
Since the mass of a segment of this spring is dm = (m/l) dx, the kinetic energy for each of its segment would be given by:
dK = 1/2 × (dm)Vx²
This ultimately implies that, the kinetic energy of this block-spring when the block has a speed (v) is given by:
K.E = 1/2 × Mv² + 1/2 × ¹∫₀((x²v²/l²)m/ldx
K.E = 1/2 × (M + m/3)v².
Read more on kinetic energy here: brainly.com/question/15848455
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Answer:
B = 1058.4 N
Explanation:
Given that,
The volume of a metal block, V = 0.09 m³
The density of fluid, d = 1200 kg/m³
We need to find the buoyant force when it's Completely immersed in brine. The formula for the buoyant force is given by :

g is acceleration due to gravity

So, the required buoyant force is 1058.4 N.