Answer:
539N
Explanation:
Parameters given:
Mass of person = 66kg
Mass of parachute = 4kg
Downward acceleration = 2.1 m/s²
The total force acting on the system is the sum of the force of gravity and the force due to air acting opposite gravity:
F = mg - F(a)
Where g = acceleration due to gravity
Force is given as:
F = ma
=> ma = mg - F(a)
=> F(a) = mg - ma
F(a) = m(g - a)
m is the mass of the entire sustem
m = 66 + 4 = 70kg
=> F(a) = 70(9.8 - 2.1)
F(a) = 70 * 7.7
F(a) = 539N
The upward force on the open parachute from the air is 539N
In accordance with the definition of density as r = m/V, in order to determine the density of
matter, the mass and the volume of the sample must be known.
The determination of mass can be performed directly using a weighing instrument.
The determination of volume generally cannot be performed directly. Exceptions to this rule
include
· cases where the accuracy is not required to be very high, and
· measurements performed on geometric bodies, such as cubes, cuboids or cylinders, the volume
of which can easily be determined from dimensions such as length, height and diameter.
· The volume of a liquid can be measured in a graduated cylinder or in a pipette; the volume of
solids can be determined by immersing the sample in a cylinder filled with water and then
measuring the rise in the water level.
Because of the difficulty of determining volume with precision, especially when the sample has a
highly irregular shape, a "detour" is often taken when determining the density, by making use of the
Archimedean Principle, which describes the relation between forces (or masses), volumes and
densities of solid samples immersed in liquid:
From everyday experience, everyone is familiar with the effect that an object or body appears to
be lighter than in air – just like your own body in a swimming pool.
Figure 3: The force exerted by a body on a spring scale in air (left) and in water (right)
Answer: A
Causing air molecules to vibrate
Explanation:
Sound is made by vibrations. And it is an energy. When any object vibrates, it causes movement in the air particles. These particles bump into the particles close to them, which makes them vibrate too causing them to bump into more air particles. This movement, called sound waves, keeps going until they run out of energy.
3,728.2271 miles per hour please mark brainliest
Answer:
Angle of refraction
Explanation:
The incident ray is the ray before it reaches the surface.
The refracted ray is the ray after it reaches the surface.
n₁ is called the index of incidence.
n₂ is called the index of refraction.
θ₁ is called the angle of incidence.
θ₂ is called the angle of refraction.
They are related by Snell's law:
n₁ sin θ₁ = n₂ sin θ₂
