Answer:
D. Cooler
Explanation:
The Sun's surface has a temperature ranging from 6 000 Kelvin, thus it is very hot. The radioactive reaction in the core of the Sun is a nuclear fusion reaction. This reaction ensures continuous release of high energy from the surface of the Sun.
But during the reaction, some parts becomes cooler than other parts on its surface. Which is due to the release of high amount of energy into space. The Sun's spot can be found in the cooler part of the Sun.
Answer:
40 m/s.
Explanation:
From the question given above, the following data were obtained:
Initial velocity (u) = 60 m/s
Height (h) = 100 m
Acceleration due to gravity (g) = 10 m/s²
Final velocity (v) =?
The velocity at height 100 m can be obtained as follow:
v² = u² – 2gh (since the ball is going against gravity)
v² = 60² – (2 × 10 × 100)
v² = 3600 – 2000
v² = 1600
Take the square root of both side
v = √1600
v = 40 m/s
Thus, velocity at height 100 m is 40 m/s
<span>So we want to know why the does a bouncing ball rise to a lower height with each bounce. So lets say the ball is first on some height h. There it has potential energy Ep=m*g*h. Then as the ball starts falling to the ground the energy converts to kinetic energy Ek=(1/2)*m*v^2. When the ball falls to the ground, the kinetic energy transforms to elastic energy because the ball deforms as it hits the ground and some small quantity of heat. The heat goes to the air and to the ground so it gets removed from the system. So there is less energy in the system to be converted back to kinetic energy as the ball starts to rise in height again. Thats why the ball is not able to get bact to the same height as it started from. </span>
For rectilinear motions, derived formulas all based on Newton's laws of motion are formulated. The equation for acceleration is
a = (v2-v1)/t, where v2 and v1 is the final and initial velocity of the rocket. We know that at the end of 1.41 s, the rocket comes to a stop. So, v2=0. Then, we can determine v1.
-52.7 = (0-v1)/1.41
v1 = 74.31 m/s
We can use v1 for the formula of the maximum height attained by an object thrown upwards:
Hmax = v1^2/2g = (74.31^2)/(2*9.81) = 281.42 m
The maximum height attained by the model rocket is 281.42 m.
For the amount of time for the whole flight of the model rocket, there are 3 sections to this: time at constant acceleration, time when it lost fuel and reached its maximum height and the time for the free fall.
Time at constant acceleration is given to be 1.41 s. Time when it lost fuel covers the difference of the maximum height and the distance travelled at constant acceleration.
2ax=v2^2-v1^2
2(-52.7)(x) = 0^2-74.31^2
x =52.4 m (distance it covered at constant acceleration)
Then. when it travels upwards only by a force of gravity,
d = v1(t) + 1/2*a*t^2
281.42-52.386 = (0)^2+1/2*(9.81)(t^2)
t = 6.83 s (time when it lost fuel and reached its maximum height)
Lastly, for free falling objects, the equation is
t = √2y/g = √2(281.42)/9.81 = 7.57 s
Therefore, the total time= 1.41+6.83+7.57 = 15.81 s
