A star is a large ball of gas that generates its own energy by fusing hydrogen atoms to make helium. It is held together by its own gravity. ... Stars come in a variety of sizes and compositions, which determine their amount of energy and gravity.
Answer:
d). X-rays
Explanation:
X -rays are also called photons. They are a packet of electro magnetic radiation. X rays originate from the shell of the electron. X rays are highly penetrating, and have a shorter wavelength than alpha particles and the beta particles. They are similar to the gamma rays which are also has a high penetrating power and easily pass through the human body.
Thus X rays can penetrate a skin tissue upto 2 cm thickness.
Answer:
Acceleration =4.42m/s^2
Explanation:
As the mug is not sliding on the car roof ,there must be static friction between the car and the mug. The maximum limit of static friction that can act is given by:
Kmg
Where I is coefficient of static friction between car roof and mug
m = mass of mug
g= acceleration due to gravity
Acceleration of the car= Kmg
Acceleration = 1.1 × 0.41 × 9.8 =4.42m/s
<span>engine makes the car go forward but, it is the engine that makes the wheels go.
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Answer:
B. Truck X had a head start, not truck Y.
Explanation:
Let's see what data can we obtain from this information.
Truck X's position changed from point (0,20) to point (2.8,50). That means that it started on the 20th kilometer and in the next 2.8 hours reached 50 km. It's velocity, then, is v1 = (s2 - s1) / t
v1 = (50 - 20) / 2.8
v1 = 10.7 km/h
Since it started from 20th km that means it had head start and since its line on the graph is straight, that means that its velocity was constant and that it didn't change direction.
Truck Y's position changed from the origin (0,0) to the point (5,20). That means it crossed 20 km in 5 hours, so its velocity is v2 = 20 / 5
v2 = 4 km/h
Again, since its line on the graph is straight, its velocity is constant and it did not change direction.
Now, knowing this, we can see that Rosa's mistake was to claim that truck Y had head start.
