Câu 3: \(h=\dfrac{1}{2}gt^2=\dfrac{1}{2}.9,8.3^2=44,1\left(m\right)\)
Câu 4: \(v=gt=g.\sqrt{\dfrac{2h}{g}}=\sqrt{2hg}=\sqrt{2.4,9.9,8}=9,8\left(m/s\right)\)
Câu 5: \(v=gt=\sqrt{2hg}=\sqrt{2.10.9,8}=14\left(m/s\right)\) (g = 9,8m/s2)
Câu 6: \(s=\dfrac{1}{2}gt^2\Leftrightarrow t=\sqrt{\dfrac{2s}{g}}=\sqrt{\dfrac{2.45}{10}}=3\left(s\right)\)
Câu 7: \(v=gt=\sqrt{2hg}=\sqrt{2.5.10}=10\left(m/s\right)\) (g=10m/s2)
Câu 8: \(h=\dfrac{1}{2}gt^2\Leftrightarrow t=\sqrt{\dfrac{2h}{g}}=\sqrt{\dfrac{2.5}{10}}=1\left(s\right)\)
Câu 9: \(h=\dfrac{1}{2}gt^2\Leftrightarrow t=\sqrt{\dfrac{2h}{g}}=\sqrt{\dfrac{2.500}{10}}=10\left(s\right)\)
Câu 10:
Ta có: \(h=\dfrac{1}{2}gt^2\Leftrightarrow t=\sqrt{\dfrac{2h}{g}}=1\)
\(\Rightarrow4h=h_1=\dfrac{1}{2}gt^2\Leftrightarrow t=\sqrt{\dfrac{4.2h}{g}}=\sqrt{4}.1=2\left(s\right)\)
\(h=\dfrac{1}{2}gt^2=\dfrac{1}{2}.9,8.3^2=44,1\left(m\right)\)
