The diagram below shows a boat moving north in a river at 3m/s while the current in the river moves south at 1 m/s.
1 answer:
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Answer:
Explanation:
Electric field due to a point charge Q at a point at distance d is given by the relation
E =
Since Q1 and Q2 are of the same magnitude and distance , so they will create eletric field of same magnitude. Similarly field due to rest of the charges will also be same.
The charges are situated on the corners of a square in such a way that
equal charges of Q1 and Q3 are situated on the diametrically opposite corners of the square. Fields due to these two charges will be equal and opposite in direction. Therefore net field due to these two charges will be zero.
On the same ground, we can say that field due to Q2 and Q4 at the centre will be equal and opposite and therefore they will cancel out each other. Net field at the centre will be zero
Overall, net field due to all the four charges will be zero
1. A. 6.00 sec
The graph shows the velocity of an object (y-axis) versus the time (x-axis). In order to find when the magnitude of the velocity reaches 36.00 km/h, we should find the time t (x-coordinate) at which the velocity (y-coordinate) is 36.
By looking at the graph, we see that this occurs when t=6.00 s.
2. A. positive acceleration
In a velocity-time graph like this one, the slope of the curve corresponds to the acceleration of the object. In fact, acceleration is defined as:
where is the variation of velocity and
is the variation of time. We see that this quantity corresponds to the slope of the curve in the graph (in fact,
represents the increment of the y coordinate, while
represents the increment of the x coordinate). So, a positive slope means a positive acceleration: in this case, the slope is positive, so the acceleration is also positive.