2km*1000=2000m
S=ut+1/2at^2
a=0,thus s=ut
2000=90t
t=2000/90
=22.22s(to 4 s.f)
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The motorized toy boat experiences a net force of 0 N between 4 s and 8 s.
The motorized toy boat moves at 8 m/s (u) at 4 s and at 8 m/s (v) at 8 s. We can calculate the acceleration (a) in that period using the following kinematic expression.

The object with a mass (m) of 2.0 kg experiences an acceleration of 0 m/s². We can calculate the net force (F) in that period using Newton's second law of motion.

The motorized toy boat experiences a net force of 0 N between 4 s and 8 s.
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Answer:
The electron has a negative charge and is found outside of the nucleus.
Explanation:
1.) Neutrons have no charge, not a negative charge.
2.) Neutrons are found inside the nucleus, not outside.
3.) Protons have a positive charge.
X-ray formation
Energy difference in the first ionization of the same group of elements
Differential linear emission spectra of different elements
Explanation:
The formation of x-ray, energy difference in the first ionization of the same group of elements and differential linear emission spectra of different elements can be justified by the Bohr model of the atom.
- According to Neil Bohr, in an atom, the extranuclear part consists of electrons in specific spherical orbits around the nucleus.
- Bohr's model explained the discrete lines in atomic spectrum of different elements.
- Due to excitation of electrons, some rays are given off. Some of these are energetic like x-rays.
- The energy difference between the first ionization of the same group of elements is a proof that electrons are in specific spherical orbits.
- The higher the energy the level, the ease at which electrons can be removed and the lower the ionization energy.
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Answer:

Explanation:
<u>Accelerated Motion</u>
It occurs when an object changes its speed over time. If the changes in speed are uniform, then the acceleration is constant, positive if the speed increases, negative if the speed decreases.
The acceleration is calculated as follows:

The aeroplane starts with a speed of vo=62 m/s and reaches a speed of vf=6 m/s in t=35 s.
The acceleration is:

