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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Answer:
2.98 second
Explanation:
The severity index is defined by :
a is dimensionless constant that equals the number of multiples of g
Conditions are given as :
Initial velocity, u = 0
Acceleration, a = 34 m/s²
Final velocity, v = 16.4 km/h = 4.56 m/s
We can find t from the above data as follows :
As a is the acceleration that is multiple of g.
So,
So,
Severity index,
Hence, the severity index for the collision is 2.98 seconds.