Alannah added a strip of zinc to a beaker containing a solution of copper

Anvisha [2.4K]

The speed of the rock at 20 m is 34.3 m/s

Explanation:

We can solve this problem by using the law of conservation of energy: the mechanical energy of the rock, sum of its potential energy + its kinetic energy) must be conserved in absence of air resistance. So we can write:

$U_i +K_i = U_f + K_f$

where :

$U_i$ is the initial potential energy

$K_i$ is the initial kinetic energy

$U_f$ is the final potential energy

$K_f$ is the final kinetic energy

The equation can also be rewritten as follows:

$mgh_i + \frac{1}{2}mu^2 = mgh_f + \frac{1}{2}mv^2$

where:

m = 100 kg is the mass of the rock

$g=9.8 m/s^2$ is the acceleration of gravity

$h_i = 80$ is the initial height

u = 0 is the initial speed (the rock starts at rest)

$h_f = 20 m$ is the final height of the rock

v is the final speed when h = 20 m

And solving for v, we find:

$v=\sqrt{2g(h_i-h_f)}=\sqrt{2(9.8)(80-20)}=34.3 m/s$

Learn more about kinetic energy and potential energy here:

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5 0

3 years ago

What is air masses? And 5 effect of it

zhannawk [14.2K]

Answer:

an air mass is a volume of air defined by its temperature and water vapor content. Air masses cover many hundreds or thousands of miles, and adapt to the characteristics of the surface below them. They are classified according to latitude and their continental or maritime source regions. Colder air masses are termed polar or arctic, while warmer air masses are deemed tropical. Continental and superior air masses are dry while maritime and monsoon air masses are moist. Weather fronts separate air masses with different density (temperature and/or moisture) characteristics. Once an air mass moves away from its source region, underlying vegetation and water bodies can quickly modify its character.When winds move air masses, they carry their weather conditions (heat or cold, dry or moist) from the source region to a new region. When the air mass reaches a new region, it might clash with another air mass that has a different temperature and humidity. This can create a severe storm.

Air masses can affect the weather because of different air masses that are different in temperature, density, and moisture. When two different air masses meet a front forms. This is one way air masses effect our weather.

5 0

3 years ago

A ball with a mass of 275 g is dropped from rest, hits the floor, and re-bounds upward. If the ball hits the floor with a speed

disa [49]

Answer:

a) $\Delta p = 1.350\,\frac{kg\cdot m}{s}$ , b) $\Delta p' = -0.454\,\frac{kg\cdot m}{s}$ , c) D. The magnitud of the change in the ball's momentum.

Explanation:

a) The magnitude of the change in the ball's momentum is:

$\Delta p = (0.275\,kg)\cdot \left[\left(1.63\,\frac{m}{s} \right)-\left(-3.28\,\frac{m}{s} \right)\right]$

$\Delta p = 1.350\,\frac{kg\cdot m}{s}$

b) The change in the magnitude of the ball's momentum:

$\Delta p' = (0.275\,kg)\cdot \left[(1.63\,\frac{m}{s} )-(3.28\,\frac{m}{s} ) \right]$

$\Delta p' = -0.454\,\frac{kg\cdot m}{s}$

c) The magnitude of the change in the ball's momentum is more directly related to the net force acting on the ball, as it measures the effect of the force on change in ball's motion at measured time according to the Impact Theorem. So, the right answer is option D.

3 0

3 years ago

Heptane and water do not mix, and heptane has a lower density (0.684 g/mL) than water (1.00 g/mL). A graduated cylinder contains

lakkis [162]

Given that the density of heptane is