Answer:
With the exception of natural gas fossil fuel energies have seen an overall decrease since year 2000.
Explanation:
Just observe the graph
The Fossil fuels include-Petroleum ,coal and natural gases.
- The graph of these goes fastly up during 20th century but ,then it stabled at the peak then has not shown any solid increase .
- Observe other energy sources graph ,nuclear energy etc have shown quite speedy increase .
Option C is correct
Answer:
(i) -556 rad/s²
(ii) 17900 revolutions
(iii) 11250 meters
(iv) -55.6 m/s²
(v) 18 seconds
Explanation:
(i) Angular acceleration is change in angular velocity over time.
α = (ω − ω₀) / t
α = (10000 − 15000) / 9
α ≈ -556 rad/s²
(ii) Constant acceleration equation:
θ = θ₀ + ω₀ t + ½ αt²
θ = 0 + (15000) (9) + ½ (-556) (9)²
θ = 112500 radians
θ ≈ 17900 revolutions
(iii) Linear displacement equals radius times angular displacement:
s = rθ
s = (0.100 m) (112500 radians)
s = 11250 meters
(iv) Linear acceleration equals radius times angular acceleration:
a = rα
a = (0.100 m) (-556 rad/s²)
a = -55.6 m/s²
(v) Angular acceleration is change in angular velocity over time.
α = (ω − ω₀) / t
-556 = (0 − 15000) / t
t = 27
t − 9 = 18 seconds
Answer: (B) There is complete destructive interference between the incoming and reflected waves
Explanation:
For example, if you pluck a guitar the waves will travel back and forth. They consist of nodes and anti-nodes. It is created, when the wave traveling to one side and bounces of the other end and comes back. As it travels to the other side, it is reflected thus, comes back. So standing waves occurs when there is interference.
When the wave is produced, the points where the string is not moving are called nodes and where they are moving are called anti-nodes. The positions where nodes are produced, destructive interference occurs and where anti-nodes are produced, constructive interference occurs
<h3>A boy who is riding his bicycle, moves with an initial velocity of 5 m/s. Ten second later, he is moving at 15 m/s. What is his acceleration?</h3>
<h3>Initial Velocity (<em>u</em>) - 5 m/s</h3><h3>Final Velocity (<em>v</em>) - 15 m/s</h3><h3>Time (<em>t</em>) - 10 sec</h3>
<h3>If the velocity of an object changes from an initial value <em>u </em>to the final value <em>v </em>in time <em>t,</em><em> </em>the acceleration <em>a</em> is, </h3><h3>
</h3><h3>
</h3>
<h3>His acceleration is </h3><h3>
</h3><h3 /><h3 />
Answer:
E) 80 N/m
Explanation:
Given;
mass of the block, m = 4.8 kg
displacement of the block, x = -0.5 m
velocity of the block, v = -0.8 m/s
acceleration of the block, a = 8.3 m/s²
From Newton's second law of motion;
F = ma
Also, from Hook's law;
F = -Kx
where;
k is the force constant
Thus, ma = -kx
k = -ma/x
k = -(4.8 x 8.3) / (-0.5)
k = 79.7 N/m
k ≅ 80 N/m
Therefore, the force constant of the spring is closest to 80 N/m
