Answer:
B - Earth's path around the Sun
Explanation:
Answer:
12.31 m/s
Explanation:
If we recall from the previous knowledge we had about speed,
we will know that:
speed = distance/ time.
As such:
The average speed of the rider bicycle is
average speed = total distance/ total time
Mathematically, it can be computed as:
![v_{avg} = \dfrac{d+d}{\dfrac{d}{v_1}+ \dfrac{d}{v_2}}](https://tex.z-dn.net/?f=v_%7Bavg%7D%20%3D%20%5Cdfrac%7Bd%2Bd%7D%7B%5Cdfrac%7Bd%7D%7Bv_1%7D%2B%20%5Cdfrac%7Bd%7D%7Bv_2%7D%7D)
![v_{avg} = \dfrac{2d}{\dfrac{d}{10 \ m/s}+ \dfrac{d}{16 \ m/s}}](https://tex.z-dn.net/?f=v_%7Bavg%7D%20%3D%20%5Cdfrac%7B2d%7D%7B%5Cdfrac%7Bd%7D%7B10%20%5C%20m%2Fs%7D%2B%20%5Cdfrac%7Bd%7D%7B16%20%5C%20m%2Fs%7D%7D)
![v_{avg} = \dfrac{2}{\dfrac{1}{10 \ m/s}+ \dfrac{1}{16 \ m/s}}](https://tex.z-dn.net/?f=v_%7Bavg%7D%20%3D%20%5Cdfrac%7B2%7D%7B%5Cdfrac%7B1%7D%7B10%20%5C%20m%2Fs%7D%2B%20%5Cdfrac%7B1%7D%7B16%20%5C%20m%2Fs%7D%7D)
![v_{avg} = \dfrac{2}{\dfrac{13}{80 \ m/s}}](https://tex.z-dn.net/?f=v_%7Bavg%7D%20%3D%20%5Cdfrac%7B2%7D%7B%5Cdfrac%7B13%7D%7B80%20%5C%20m%2Fs%7D%7D)
![\mathbf{v_{avg} =12.31 \ m/s}](https://tex.z-dn.net/?f=%5Cmathbf%7Bv_%7Bavg%7D%20%3D12.31%20%5C%20m%2Fs%7D)
Answer:
7.6 s
Explanation:
Considering kinematics formula for final velocity as
![v^{2}=u^{2}+2as](https://tex.z-dn.net/?f=v%5E%7B2%7D%3Du%5E%7B2%7D%2B2as)
Where v and u are final and initial velocities, a is acceleration and s is distance moved.
Making v the subject then
![v=\sqrt{u^{2}+2as}](https://tex.z-dn.net/?f=v%3D%5Csqrt%7Bu%5E%7B2%7D%2B2as%7D)
Substituting 8.8 m/s for u, 138 m for s and 2.45 m/s2 for a then
![v=\sqrt{8.8^{2}+2*2.45*138}\\v=27.45 m/s](https://tex.z-dn.net/?f=v%3D%5Csqrt%7B8.8%5E%7B2%7D%2B2%2A2.45%2A138%7D%5C%5Cv%3D27.45%20m%2Fs)
Also, v=u+at and making t the subject of the formula
![t=\frac {v-u}{a}](https://tex.z-dn.net/?f=t%3D%5Cfrac%20%7Bv-u%7D%7Ba%7D)
Substituting 27.45 m/s for v, 8.8 m/s for u and 2.45 m/s for a then
![t=\frac {27.45-8.8}{2.45}=7.6122448979591\approx 7.6s](https://tex.z-dn.net/?f=t%3D%5Cfrac%20%7B27.45-8.8%7D%7B2.45%7D%3D7.6122448979591%5Capprox%207.6s)
Therefore, it needs 7.6 seconds to travel