Which of the following is the best definition of an isotope?

Small, slowly moving spherical particles experience a drag force given by Stokes' law: Fd = 6πηrv where r is the radius of the p

Dominik [7]

Answer:

Explanation:

At the time of a body achieving terminal velocity, the drag force becomes equal to the weight of the body less the buoyant force by the surrounding medium which can be represented by the following equation

$\frac{4\pi\times r^3(d-\rho)}{3} =6\pi\times n\times r\times v$

Where r is radius of the body , d is density of the material of the body σ is density of the medium and n is coefficient of viscosity of the medium and v is terminal velocity.

Simplifying

v = $\frac{2\times r^2(d-\rho)}{9\times n}$

Assuming the value of density of air as 1.225 kg/m³ and putting other given values in the formula we get

v = $[tex]\frac{2\times (1.2\times10^{-5})^2(2182-1.225)}{9\times 1.8\times10^{-5}}$ [/tex]

v = 387 x 10⁻⁵ m/s

Terminal velocity = 387 x 10⁻⁵ m/s

Time taken to fall a distance of 100 m

= $\frac{100}{387\times10^{-5}}$

= 2.6 x 10⁴ s.

5 0

3 years ago

When a car driving up a hill with constant speed: I. its kinetic energy is decreasing. II. its potential energy is constant. III

madam [21]

A car driving up a hill at a constant speed experiences no change in its kinetic energy while it's potential energy increases with increasing height, thus none of the options are correct.

Understanding the concept

Consider a car moving up the hill at a constant speed as shown in the figure below. The following forces act on the car:

N is the normal reaction force acting in an upward direction

f_s is the static friction force exerted due to friction between the road and the tires of the car
f_k is the rolling friction force in the direction opposing that of the tire
mg is the force acting in a downward direction.

θ is the angle of inclination.

Here as the car is moving up the hill at a constant speed, the net force exerted on the car is zero. Also, the kinetic energy of the car will not change as its velocity is constant and the potential energy will change with increasing height. Thus, none of the given options are correct.

Learn more about motion on an incline here:

<u>brainly.com/question/13513083</u>

#SPJ4