91影视

$$\begin{gathered} \mathrm{Total}\mathrm{mass}\left(m\right)=630\mathrm{kg} \\ \mathrm{Lenght}\left(s\right)=80.0\mathrm{m}\mathrm{and}\mathrm{is}\mathrm{inclined}\mathrm{at}\mathrm{a}\mathrm{constant}\mathrm{angle}\mathrm{of}10.2掳\mathrm{with}\mathrm{the}\mathrm{horizontal}. \\ \mathrm{Force}\left(f\right)=62.0\mathrm{N} \\ \mathrm{Initial}\mathrm{velocity}\mathrm{is},u=6.20\mathrm{m}/\mathrm{s} \end{gathered}$$

The problem deals with Newton鈥檚 second law of motion. It tells us that the acceleration a of an object is affected by the net force F acting upon the object and the mass of m the object.

Formula:

F = ma

The component of the weight along the incline (with downhill understood as the positive direction) is,

$mg\sin 胃$

Where m is the mass and is$胃$ the angle.

We can write the balance force equation as,

$mg\sin 胃-f=ma$

Substitute the values in the above equation, and we get,

$$\begin{gathered} 630脳9.8脳\sin 10.2掳-62=630脳a \\ a=1.937\mathrm{m}/{\mathrm{s}}^2 \\ \mathrm{a}=1.64\mathrm{m}/{\mathrm{s}}^2 \end{gathered}$$

We know that from the equation of motion, we can write the expression for distance as,

$s=ut+1/2a{t}^2$

Substitute the values in the above equation, and we get,

$80.0\mathrm{m}=\left(6.20\mathrm{m}/\mathrm{s}\right)\mathrm{t}+\left(1/2\right)\left(1.64\mathrm{m}/{\mathrm{s}}^2\right){\mathrm{t}}^2$

The above equation is a quadratic equation of t; we can find the root as,

t = 6.80 s

Thus, the bobsled takes 6.80 s to come down straightaway.

$\mathrm{Force}\left(\mathrm{f}\right)=42.0\mathrm{N}$

We can write the balance force equation as,

$mg\sin 胃-f=ma$

Substitute the values in the above equation, and we get,

$$\begin{gathered} 630脳9.8脳\sin 10.2掳-42=630脳a \\ a=1.66\mathrm{m}/{\mathrm{s}}^2 \end{gathered}$$

We know that from the equation of motion, we can write the expression for distance as,

$s=ut+1/2a{t}^2$

Substitute the values in the above equation, and we get,

$80.0\mathrm{m}=\left(6.20\mathrm{m}/\mathrm{s}\right)\mathrm{t}+\left(1/2\right)\left(1.66\mathrm{m}/{\mathrm{s}}^2\right){\mathrm{t}}^2$

The above equation is a quadratic equation of t; we can find the root as,

t = 6.76 s

Thus, the bobsled takes 6.76 s to come down the straightaway.