Part A)
As we know that spring force is given by
F = kx
here x = stretch in the spring from natural length
So here when spring reaches to its natural length
Force due to spring = 0
so acceleration = 0
Part b)
When spring is compressed from its natural length it will have elastic potential energy in it
so it is given by

now we know that there is no friction in it so maximum kinetic energy of the launcher must be equal to the elastic potential energy of the spring

here we have
k = 70 N/m
x = 0.4 m


Part c)
Now to find the speed we know that



so its speed is 6.11 m/s
Question: calculate their densties in Si unit.
200mg,0.0004m³
Answer:
0.5 kg/m³
Explanation:
Applying,
D = m/V........................ Equation 1
Where D = density, m = mass, V = volume.
From the question,
Given: m = 200 mg = (200/1000000) kg = 2.0×10⁻⁴ kg, V = 0.0004 m³ = 4.0×10⁻⁴ m³
Substitute these values into equation 1
D = (2.0×10⁻⁴ kg)/(4.0×10⁻⁴)
D = 2/4
D = 0.5 kg/m³
Hence the density in S.I unit is 0.5 kg/m³
The recycling of glass, plastic, and metal would highly reduce the amount of the waste being sent to the local landfill. The large plastic container, fiberboards, etc, are removed by hand for this. This sorting makes it easy to recycle and reuse the plastic and fiber materials.
Answer:
1.5 m
Explanation:
Length. L = 12 m
Width, W = 16 m
Area, A = 12 x 16 = 192 m^2
Let the width of pavement be d.
The new length, L' = 12 + 2d
the new width, W' = 16 + 2d
New Area, A' = L' x W' = (12 + 2d)(16 + 2d) = 192 + 56 d + 4d^2
Difference in area = A' - A
285 = 192 + 56 d + 4d^2 - 192
93 = 56 d + 4d^2
4d^2 + 56 d - 93 = 0

\
d = 1.5 m
Thus, the width of the pavement is 1.5 m.
Answer:
That's simply because any electromagnetic wave longer than a microwave is called a radio wave. Microwaves: Obviously used for cooking in microwave ovens, but also for transmitting information in radar equipment. Microwaves are like short-wavelength radio waves. Typical size: 15cm (the length of a pencil).