Answer:
the energy when it reaches the ground is equal to the energy when the spring is compressed.
Explanation:
For this comparison let's use the conservation of energy theorem.
Starting point. Compressed spring
Em₀ = K_e = ½ k x²
Final point. When the box hits the ground
Em_f = K = ½ m v²
since friction is zero, energy is conserved
Em₀ = Em_f
1 / 2k x² = ½ m v²
v = 
x
Therefore, the energy when it reaches the ground is equal to the energy when the spring is compressed.
Answer:
By a factor 9
Explanation:
The intensity of a sound wave is proportional to the square of the amplitude of the wave:
where
I is the intensity
A is the amplitude of the wave
In this problem, the amplitude of the sound wave is increased by a factor 3:
A' = 3A
So the intensity would change by
So, the intensity would increase by a factor 9.
Kinetic
energy is the energy that is possessed by an object that is moving. It is
calculated by one-half the product of the mass and the square of the velocity
of the object. We calculate as follows:<span>
For the truck,
KE = mv^2 / 2
KE = 20000 kg (110 km/h (1 h/3600 s)(1000 m / 1 km))^2 / 2
KE = 611111.11 J
For the astronaut,
KE = 80.0 kg (27500 km/h</span>(1 h/3600 s)(1000 m / 1 km)<span>)^2/2
KE = 611111.11 J
The kinetic energy possessed by the two bodies are the same.
</span>
- Initial velocity,u = -2 m/s
- Final velocity,v = -10 m/s
- Time taken, t = 4 seconds
Find the acceleration ( a ) .
We know that,
Substituting the values in the above formula, we get
Hence,the acceleration of a body is -2 m/s².
C^2=a^2+b^2
c^2=45^2+45^2
c^2=4050
c=63.64
c=64
The answer is D.
