Achild is riding a bike at a speed of 6m/s with a total kinetic energy of 1224j. if the mass of the child is 30kg, what is the mass of the bike?

 Mass of bike = 38 kg.

Explanation:

Kinetic energy is given by the expression, , where m is the mass and v is the velocity.

Here speed of child riding bike = 6 m/s

Mass of child = 30 kg

Total kinetic energy = 1224 J

Let the mass of bike be, m kg

So, total mass of child and bike = (m + 30) kg

Substituting,

So, mass of bike = 38 kg.

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

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