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:
a) 
s
b) 3.41 mm
Explanation:
a)
We take the speed of light, c = 
m/s and the refractive index of glass as 1.517.
Speed = distance/time
Time = distance/speed
Refractive index, n = speed of light in vacuum / speed of light in medium
b)
We take the refractive index of water as 1.333.
Speed in water = speed in vacuum / refractive index of water
Distance = speed * time
d = 3.41 mm
By Newton's 2nd law of motion, F = ma, where F is force, m is mass, and a is acceleration.
Rearranging this equation to find acceleration would give us:
a = F/m
The horizontal force to the right is 10N, because the box is pushed to the right with a force of 20N, and the friction force of 10N opposes that, so:
20N - 10N = 10N
The mass is 2kg.
Putting these values into the equation gives us:
a = F/m
= 10/2
= 5ms^-2
The acceleration of the box is 5ms^-2
D. The molecules in water are constantly moving.
They are able to do this because they move around to take whatever shape of the container.
