A ) v = v o + a t ( the acceleration will be negative )
9.50 = 16.0 + a * 1.2
a * 1.2 = -16.0 + 9.50
a * 1.2 = - 6.5
a = - 6.5 : 1.2
a = - 5.4167 m/s²
F = m * a = 950 kg * 5.4167 m/s²
F = 5,145.8 N ( the average force exerted on a car during braking )
b ) d = v o - a t² / 2
d = 16.0 * 1.2 - ( 5.4167 * 1.2² / 2 ) =
= 19.20 - 3.90 = 15.30 m
The answer is c, because ball is falling so its gravitationl potential energy decreases, but it kinetic energy increases. Energy is always conserved.
Explanation:
A bearing if an angle is measured clockwise from north direction.
e.g Below the bearing of B from A is 025. (3 figures are always given). the bearing of A from B is 205°.
Answer: The five general characteristics of the nearest stars are the brightness, color, surface temperature, size, and mass.
Explanation:
The mass of a star can be described as being measured with our sun at 1 solar mass. One star can equal the size of our sun. There is one star named, Rigel, that is bigger than the Earths sun. Each star will vary in its density.
The size of the star, as stated above, can be the size of our sun and sometimes larger. The size is measured by solar radii.
Stars vary in their temp. They range anywhere from -273.15 degrees Celsius to 50,000 K. The temp is based on the Kelvin scale.
The stars brightness are always based on luminosity and magnitude.
The stars colors will vary and is based on the temperature of the surface of the star. Some stars are red in color, white in color, and some even have a bluish color.
Answer:
student A or B
Explanation:
A common demonstration is to put a ringing alarm clock or bell in the bell jar, and when the vacuum is created, you can no longer hear the sound of the clock/bell.
The bell is connected to a lab pack or batteries and rung to show pupils it can be heard under normal circumstances. The bell jar is then connected to a vacuum pump using a vacuum plate (see Fig 2) and the air is removed from inside creating a near vacuum. The bell is then again rung. This time however, it cannot be heard.
Small low voltage buzzers can be used as a bell replacement for the bell and work in exactly the same way though teachers generally prefer bells as students may be able to see the hammer moving, proving that it is actually ringing even though they cannot hear it.
Some vacuum pumps are better than others at keeping a strong vacuum though if you cannot completely lose the sound, you will at least notice the volume decreasing.
Sound is simply a series of longitudinal waves travelling from the source, through the air to our ears. Without air present, these waves cannot form and therefore sound cannot be conveyed.
In a longitudinal wave the particles oscillate back and forth in the direction of the wave movement unlike transverse waves which like waves on the sea, single particles travel up and down and not in the direction of the wave.
Because you will not be able to create a perfect vacuum, you may still be able to hear the bell ring slightly. Vibrations from the ringing bell can also travel up to the bung in the bell jar which in turn may resonate the jar slightly. This means you may hear the bell ring, however strong the vacuum. To compensate for this, try to insulate the bell as much as possible from the bell jar. Hanging the bell using elastic cord means some of the vibrations will be absorbed by the cord and not be transferred to the bell jar.
