<span>A measurement
that both magnitude and direction is a vector quantity. An example of this is a
moving car. The car exerts force due to its thrust and weight that runs in it. This
will give us the magnitude of the car. The resulting motion of the car in terms
of displacement, velocity and acceleration that determines its direction makes
it a vector quantity. On the other hand, a measurement that has only magnitude is
a scalar quantity. The energy exerted by the engine of the car is a scalar
quantity.</span>
Answer:
The electromagnetic force
Explanation:
There are four fundamental forces in nature:
- Gravitational force: it is the force that acts between any particles having mass. It is relevant only on very large scales (planets, stars), since it is the weakest of the 4 forces, so very large masses are needed in order to produce relevant effects.
- Electromagnetic force: it is the force that acts between particles with electric charge. It can be attractive or repulsive. It is the main force that acts between atoms and molecules.
- Strong nuclear force: it is the force that keeps the protons and the neutrons together inside the nucleus. It acts only on very short scales (only within the nucleus of the atom)
- Weak nuclear force: it is the force responsible for the radioactive decays of certain nuclei. It also acts on very short scales.
Therefore, the force that is responsible for binding atoms together to form molecules is the electromagnetic force.
Answer:
option (c)
Explanation:
90% of the body is submerged in water.
Now it is immersed in an unknown liquid whose density is less than the density of water.
Buoyant force acting on the body depends on the volume immersed, density of liquid and gravity.
As the density of liquid is less than the density of water, so the buoyant force acting on the body by the unknown liquid is less than water. So it is submerged less than 90% in this liquid.
The acceleration due to gravity serves as the centripetal acceleration of the objects that orbits the Earth. The centripetal acceleration due to gravity is calculated through the equation,
a = v²/r
where v is the speed and r is the radius. Substituting the known values to the equation,
9.8 m/s² = (420 m/s)² / r
The value of r from the equation is 18000 m or equal to 18 km.
<em>Answer: 18 km</em>
When you talk about rate, you will expect that it will be in terms of a time unit. It measures how fast it is going. So, you would expect that the denominator is in time units. For the movement, you can measure this with either distance or velocity.
So, for the first variety, you would need distance and time to measure the rate of how far you go at a certain time. It is also called as velocity. For the second variety, you would need velocity and time to measure the rate of how fast you are going at a certain interval. It is also called as acceleration.
