Answer:
A. Repeat the experiment to be sure the results are valid.
Answer:
1) a block going down a slope
2) a) W = ΔU + ΔK + ΔE, b) W = ΔE, c) W = ΔK, d) ΔU = ΔK
Explanation:
In this exercise you are asked to give an example of various types of systems
1) a system where work is transformed into internal energy is a system with friction, for example a block going down a slope in this case work is done during the descent, which is transformed in part kinetic energy, in part power energy and partly internal energy that is represented by an increase in the temperature of the block.
2)
a) rolling a ball uphill
In this case we have an increase in potential energy, if there is a change in speed, the kinetic energy also increases, if the change in speed is zero, there is no change in kinetic energy and there is a change in internal energy due to the stationary rec in the point of contact
W = ΔU + ΔK + ΔE
b) in this system work is transformed into internal energy
W = ΔE
c) There is no friction here, therefore the work is transformed into kinetic energy
W = ΔK
d) if you assume that there is no friction with the air, the potential energy is transformed into kinetic energy
ΔU = ΔK
Acceleration = (change in speed) / (time for the change)
- 4.1 m/s² = (-9 m/s) / (time for the change)
Time for the change = (-9 m/s) / (-4.1 m/s²) = 2.2 seconds
Answer:
B according to the picture
Explanation:
Star of 3 stellar masses => red supergiant=>supernova=>neutron star
Answer:
The correct option is C
Explanation:
From the question we are told that
The initial speed of the rocket is 
The speed of the rocket engine sound is 
The final speed of the rocket is 
The speed of the sound at
would still remain V this because the speed of sound wave is constant and is not dependent on the speed of the observer(The mountain ) or the speed of the source (The rocket ).
A clear example when lightning strikes you will first see (that is because it travels at the speed of light which is greater than the speed of sound) but it would take some time before you hear the sound of the
lightning
Here we see that the speed of the lightning(speed of sound) does not affect the speed of the sound it generates