EMERGENCY! PLEASE HELP!
1 answer:
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The correct answer is option b, 63.6 kPa
Given,
The diameter of the heel, d=7 cm=0.07 m
The mass of the child, m=25 kg
The pressure is given by the ratio of the force to the area through which the force is applied.
The force applied on the floor by the child is equal to its weight.
Thus the pressure applied on the floor by the child is given by,
Where A is the area of the cross-section of the heel.
On substituting the known values,
Thus the pressure applied on the floor by the heel is 63.6 kPa
For the work-energy theorem, the work needed to stop the bus is equal to its variation of kinetic energy:
where
W is the work
Kf is the final kinetic energy of the bus
Ki is the initial kinetic energy of the bus
Since the bus comes at rest, its final kinetic energy is zero:
, so the work done by the brakes to stop the bus is
And the work done is negative, because the force applied by the brake is in the opposite direction to that of the bus motion.
where
W is the work
Kf is the final kinetic energy of the bus
Ki is the initial kinetic energy of the bus
Since the bus comes at rest, its final kinetic energy is zero:
And the work done is negative, because the force applied by the brake is in the opposite direction to that of the bus motion.