An unbalanced force of 20N acts on a 4.0kg mass what is it's acceleration
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Answer:
They will move the fridge if they all push in the same direction, but it will not move with constant velocity
Explanation:
The maximum static friction force is
(negative sign since its direction is opposite to the push applied by the people)
Sam can apply a force of 130 N, while Amir and Andre can apply a push of 65 N each, so the total force that they can apply, if they push in the same direction, will be:
This force is larger than the frictional force, so the fridge will start moving.
However, the net force on the fridge will be:
And according to Newton's second law,
where m is the mass of the fridge and a its acceleration, since the net force is not zero, then the fridge will have a non-zero acceleration, so it will not move with constant velocity.
To solve this problem it is necessary to apply the concepts related to the Kinetic Energy and the Energy Produced by the heat loss. In mathematical terms kinetic energy can be described as:
Where,
m = Mass
v = Velocity
Replacing we have that the Total Kinetic Energy is
On the other hand the required Energy to heat up t melting point is
Where,
m = Mass
Specific Heat
Change at temperature
Latent heat of fussion
Heat required to heat up to melting point,
The energy required to melt is larger than the kinetic energy. Therefore the heat of fusion of lead would be 327 ° C: The melting point of lead.