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A student connects a 1 hp motor to a bicycle. How much time will it take for the bicycle to accelerate from rest to a speed of 5.0 m/s if the combined mass of the student and the bicycle is 120 kg? (1 hp = 746 W)

Respuesta :

AMB000

Answer:

t=2s

Explanation:

The definition of power is:

[tex]P=\frac{W}{t}[/tex]

And the work-energy theorem states that:

[tex]W=\Delta K[/tex]

Since the movement starts from rest, we have that:

[tex]\Delta K=\frac{mv_f^2}{2}-\frac{mv_0^2}{2}=\frac{mv_f^2}{2}[/tex]

And putting all together:

[tex]P=\frac{mv_f^2}{2t}[/tex]

Since we want the time taken:

[tex]t=\frac{mv_f^2}{2P}[/tex]

Which for our values is:

[tex]t=\frac{(120kg)(5m/s)^2}{2(746W)}=2s[/tex]

Olajidey

Answer:

time = 2s

Explanation:

Power is:

[tex]P=\frac{W}{t}[/tex]

work-energy theorem states that:

[tex]W=\Delta K[/tex]

Since the movement starts from rest, we have that:

[tex]\Delta K=\frac{mv_f^2}{2}-\frac{mv_0^2}{2}=\frac{mv_f^2}{2}[/tex]

And putting all together:

[tex]P=\frac{mv_f^2}{2t}[/tex]

the time taken:

[tex]t=\frac{mv_f^2}{2P}[/tex]

Which for our values is:

[tex]t=\frac{(120kg)(5m/s)^2}{2(746W)}\\= 2s[/tex]

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