When practicing deep breathing, it is best to repeat the steps for
2 answers:
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6) b) 2.7 m/s
7) b) DCA
8) b) B
Explanation:
6)
In a displacement-time plot, the slope of the line is given by
where
is the change in the y-variable, so it is the displacement
is the change in the x-variable, so it is the time elapsed
So, the slope of the line in a displacement-time plot corresponds to the velocity:
Therefore, to find the velocity of the object, we have to estimate the slope of its curve.
To estimate the velocity of object B, we have to estimate the slope of the line tangent to curve B at 10 seconds.
By doing an estimate by eye, we see that the displacement of object B changes from -10 m to 0 m when time increases from about 8 s to 12 s, so the velocity is about:
So the closest option is b) 2.7 m/s.
7)
As we said in part A, the velocity of each object is given by the slope of each curve.
Therefore:
- The steeper the curve, the higher the velocity
- The less steep the curve, the lower the velocity
From the graph, we observe that, among A, C and D:
- Curve D has the largest slope (in absolute value), so object D has the largest magnitude of the velocity
- Curve C is less steep than curve C, so object C has the second largest magnitude of velocity
- Curve A is flat, so the slope is zero, so its velocity is zero
So, from greatest magnitude to lowest magnitude of velocity, we have:
b) DCA
8)
In the graph, the overall displacement of each object is given by the change in the y-variable, .
This means that the object with largest displacement is the object whose curve has the largest variation in y.
From the graph, we see that:
- Object b has the largest variation in y, from -15 m to 30 m, so
- Then, object D has the second largest displacement (in magnitude), from -15 m to 25 m,
Finally, object C has displacement
While object A has displacement zero. Therefore, the correct option is
b) B
Answer:
Explanation:
The roller coaster begins with maximum kinetic energy and no gravitational potential energy. The gravitational potential energy reaches its maximum when roller coaster is upside down at the top of the circle. The physical model for the roller coaster is constructed by means of the Principle of Energy Conservation:
The minimum velocity is:
Let assume that radio of curvature is measured in meters. Hence:
Answer:
In the case of a negatively charged rod, the field lines points radially towards the rod.
Explanation:
Field lines pointing towards the negatively charged rod are used to represent the nature of an electric field. Field lines always points in a direction, i.e If the charge is positive, field lines points radially away from the rod and if the charge is negative the field lines points radially towards the rod. So in the case of a negatively charged rod, the field lines points radially towards the rod.
