Explanation:
a) Given S(t) = 76 + 128t − 16t²
s(0) = 76 + 128 x 0 − 16 x 0² = 76 ft
s(4) = 76 + 128 x 4 − 16 x 4² = 332 ft
Displacement in 4 seconds = 332 - 76 = 256 ft
Time = 4 - 0 = 4 s
Average velocity in first 4 seconds is 64 ft/s upward
a) Given S(t) = 76 + 128t − 16t²
s(4) = 76 + 128 x 4 − 16 x 4² = 332 ft
s(8) = 76 + 128 x 8 − 16 x 8² = 78 ft
Displacement in 4 seconds = 78 - 332 = -254 ft
Time = 4 - 0 = 4 s
Average velocity in second 4 seconds is 63.5 ft/s downward
The power is 833.3 W
Explanation:
First of all, we need to calculate the work done in lifting the barbell, which is equal to the change in gravitational potential energy of the barbell:
where
mg = 1250 N is the weight of the barbell
h = 2 m is the change in height
Substituting,
Now we can calculate the power, which is equal to the work done per unit time:
where
W = 2500 J is the work done
t = 3 s is the time taken
Substituting,
Learn more about power:
#LearnwithBrainly
To solve this problem we will use the definition of the period in a simple pendulum, which warns that it is dependent on its length and gravity as follows:
Here,
L = Length
g = Acceleration due to gravity
We can realize that is a constant so it is proportional to the square root of its length over its gravity,
Since the body is in constant free fall, that is, a point where gravity tends to be zero:
The value of the period will tend to infinity. This indicates that the pendulum will no longer oscillate because both the pendulum and the point to which it is attached are in free fall.
A convergent meniscus lens is a lens that is composed of two spherical surfaces, like the on shown next:
The imaginary line that runs through the middle of the lens is the "symmetry axis".
In this type of lenses incident parallel beams of light converge in one point, as follows:
And thus we get the diagram.
