Calculate the mass (in g) of 346 cm³ of polythene. The density of polythene is 0.95 g/cm³. Give your answer to 2 decimal places.
1 answer:
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Answer:
A. The momentum of car A(5kg) is EQUAL to that of car B(0.5)
Explanation:
The moment, or impulse formula of the same forces acting on both car within 1 second is
In our case the forces are the same, the time duration of force acting on the cars are the same. Therefore, their momentum right after the force must also be the same.
Sasha is correct: No, the velocity is changing at the top so the acceleration cant be zero.
Explanation:
The acceleration of an object is equal to the rate of change in velocity of the object:
(1)
where
is the change in velocity
is the time interval
For the cart on the ramp, as the cart reaches the top of the ramp, its velocity becomes temporarily zero:
v = 0
This is the origin of Malia's mistake.
However, this only lasts a moment; in reality, its velocity is changing, in particular its direction is changing (from upward to downward).
As we can see from eq.(1), a non-zero change in velocity implies a non-zero acceleration. Therefore, Sasha is right, since the cart has a non-zero acceleration.
Learn more about acceleration:
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