dorien78
contestada

21
A bicyclist was moving at a rate of 5 m/s, and then sped up to 9 m/s. If the
cyclist has a mass of 130 kg, how much work was needed to increase his"
velocity? (Hint: Use the work-kinetic energy theorem.)
O
A. 1625 J
O
B. 6890
O C. 5265 J
O D. 3640 J

Respuesta :

The answer for the following problem is mentioned below.

  • Therefore the work done to increase the velocity is 3640 J.

Explanation:

Given:

initial speed (u) =5 m/s

final speed (v) = 9 m/s

mass of the cyclist (m) =130 kg

To solve:

Wok needed to increase the velocity (W)

We know;

initial kinetic energy ([tex]KE_{1}[/tex]) = [tex]\frac{1}{2}[/tex] × m × (u²)

initial kinetic energy ([tex]KE_{1}[/tex]) =  [tex]\frac{1}{2}[/tex] × 130 × ( 5 ×5 )

initial kinetic energy ([tex]KE_{1}[/tex]) = 65  × 25 =1625 J

final kinetic energy([tex]KE_{2}[/tex]) =   [tex]\frac{1}{2}[/tex] × m × (v²)

final kinetic energy([tex]KE_{2}[/tex]) =  [tex]\frac{1}{2}[/tex] × 130 × ( 9×9 )

final kinetic energy([tex]KE_{2}[/tex]) = 81 × 65

final kinetic energy([tex]KE_{2}[/tex]) = 5265 J

Work done (W) =ΔK.E =([tex]KE_{2}[/tex]) - ([tex]KE_{1}[/tex])

Work done (W) = 5265 - 1625 =3640 J

Work done (W) = 3640 J

Therefore the work done to increase the velocity is 3640 J.

Answer:

it is D.

Explanation: