Answer: The speed at which Maya threw the snowball at Max is 20m/s
Explanation:
Given that
Mass of snowball= 1.5-kg.
Mass of Maya= 12kg
Initial speed of Maya=2.5m/s
We use the law of conservation of momentum to calculate the speed of the snowball which depends on its own mass, the mass of Maya who threw the snowball and the initial velocity at which the snowball was thrown by Maya
Ms x Us = Mm x Um
Mass of snowball x Initial speed of Snow ball =Mass of Maya x Initial speed of Maya
1.5kg x Initial speed of Snow ball =12 kg x 2.5m/s
Initial speed of Snow ball=( 12 kg x 2.5m/s) /1.5kg
Initial speed of Snow ball =20m/s
Answer: C. good reflector of heat
Explanation:
In space, sunlight transfers heat by radiation to objects and bodies and this includes satellites and astronauts. In addition, although the peak of the sun's emission is in the visible region of the electromagnetic spectrum, a part is also emitted in infrared (transferring thermal energy or heat) and ultraviolet (especially in the upper part of the Earth's atmosphere).
That is why in space missions, objects and many satellites are covered by thin layers or sheets that reflect this thermal energy and thus avoid damaging the equipment due to high temperatures.
In this sense, among the reflective materials used are aluminum, silver, copper and gold; the latter being the most used because it does not corrode or oxidize (unlike silver and copper) and is more malleable than aluminum.
On the other hand, <u>astronauts are also vulnerable to the effects of infrared radiation, especially their eyes</u>, since the human eye has no receptors in the infrared spectrum. <u>That is why the astronaut's helmet visor is covered with a thin layer of gold to avoid the dangerous effects of solar radiation.</u>
Answer:
1)50000J
2) At the start of the trip
3) At the end of the trip
4) The higher the height above the ground, the higher the potential energy
5) As speed increases, Kinetic Energy increase
For this case we have the following equation:
h (t) = -16t ^ 2 + 36t + 36
By the time the rock hits the water we have:
-16t ^ 2 + 36t + 36 = 0
Solving the second degree polynomial we have:
t1 = -3/4
t2 = 3
We discard the negative root because we want to find the time.
Answer:
It will take for the rock to hit the water about:
t = 3 seconds
Answer:
We know that the speed of sound is 343 m/s in air
we are also given the distance of the boat from the shore
From the provided data, we can easily find the time taken by the sound to reach the shore using the second equation of motion
s = ut + 1/2 at²
since the acceleration of sound is 0:
s = ut + 1/2 (0)t²
s = ut <em>(here, u is the speed of sound , s is the distance travelled and t is the time taken)</em>
Replacing the variables in the equation with the values we know
1200 = 343 * t
t = 1200 / 343
t = 3.5 seconds (approx)
Therefore, the sound of the gun will be heard at the shore, 3.5 seconds after being fired