Equations for physic grade 9-5
1 answer:
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Answer:
16.67m/s
Explanation:
Given parameters:
Distance Pete drove = 300m
Time taken = 18s
Unknown:
Speed = ?
Solution:
Speed is the distance traveled per unit of time.
It is mathematically expressed as;
Speed =
Insert the parameters and solve;
Speed = = 16.67m/s
Answer:
r = 1.61 x 10^{11} m
Explanation:
energy radiated (H) = 2.7 x 10^31 W
surface temperature (T) = 11,000 k
assuming ε = 1 and taking σ = 5.67 x 10^{-8} W/m^{2}.K^{4}
we can find the radius of the star from the equation below
H = A x ε x σ x T^{4}
where area (A) = 4 x π x r^{2} (assuming it is a sphere)
therefore the equation becomes
H = 4 x π x r^{2} x ε x σ x T^{4}
2.7 x 10^31 = 4 x π x r^{2} x 1 x 5.67 x 10^{-8} x (11,000)^{4}
r =
r = 1.61 x 10^{11} m