Stop using it all the time for some useless things.
Part A. For this part, we use two equations for linear
motion:
<span>y = y0 + v0 t + 0.5 g t^2 --->
1</span>
<span>vf = v0 + g t --->
2</span>
First we solve for t using equation 1: y0 = 0 (initial
point at top), y = 250 m, v0 = 0 (at rest)
250 = 0.5 (9.8) t^2
t = 7.143 s
Now we solve for final velocity vf using equation 2:
vf = g t
vf = 9.8 (7.143)
vf = 70 m/s
Part B. First we solve for the time it takes for the sound
to reach the tourist.
t(sound) = 250 / 335 = 0.746 s
Therefore the total time would be:
t = 0.746 s + 0.300 s
t = 1.05 s
<span>Hence there is enough time for the tourist to get out
before the boulder hits him.</span>
Answer:
block K = 29.39 J and spring #1 Ke = 360 J
Explanation:
In this problem we have that the elastic energy of the spring becomes part kinetic energy and the part in work against the force of friction, so, to use the law of conservation of energy, the decrease in energy is the rubbing force work
= Ef - E₀
Let's look for the energies
Initial
E₀ = Ke = ½ k₁ x₁²
Final, this is just before starting to compress the spring
Ef = Ke = ½ m v²
The work of the rubbing force is
= -fr x
Let's write Newton's second law the y axis
N-W = 0
N = W
fr = μ N
fr = μ mg
Let's replace
-μ mg x = ½ m v² - ½ k₁ x₁²
v² = 2/m (½ k₁ x1₁² -μ mg x)
v² = 2/6 (½ 2000 0.6²2 - 0.5 6 9.8 1) = 1/3 (360 - 29.4)
v = 3.13 m / s
With this value we calculate the energy of the block
K = ½ m v²
K = ½ 6 3.13²
K = 29.39 J
Calculate eenrgy of the spring ke 1
Ke = ½ k₁ x₁²
Ke = ½ 2000 0.60²
Ke = 360 J
The smallest perimeter of the rectangle is of value 150 cm.
Given:
The area of the rectangle, A = 1350 cm²
Calculation:
Let the length of the rectangle be 'x'
the breadth of the rectangle be 'y'
We know that the area of a rectangle is given as:
A = (x) × (y)
Applying values in the above equation we get:
xy = 1350 cm²
Factorizing the value of 1350, the possible values of length and breadth of the rectangle is as listed below:
x (cm) y (cm)
1350 × 1
675 × 2
450 × 3
270 × 5
225 × 6
150 × 9
135 × 10
90 × 15
75 × 18
54 × 25
50 × 27
45 × 30 (least possible value)
Thus, the smallest perimeter of the rectangle can be calculated as:
P = 2 (x + y)
= 2 (45 + 30)
= 150 cm
Therefore, the smallest perimeter that the rectangle will have is 150 cm.
Learn more about factorization here:
<u>brainly.com/question/9231261</u>
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Science based on properties of matter and energy