A. when it reaches the top of its flight
potential energy increases as the height of the object does, and the highest point of a ball's flight is when it reaches the top.
The correct graph is <u>D</u>.
The graph <em>A</em> is a straight line sloping downwards and it shows that the speed of the body is decreasing at a constant rate. Therefore, this s a graph of a body that is under a constant deceleration.
The graph B is a straight line which slopes upwards. Hence the graph shows that the speed of the body increases at a constant rate. Therefore, this is a graph of a body that is accelerating at a constant rate.
The graph C is curved line, which curves upwards. The slope of the curve increases with time. This is therefore, a graph of a body which is under increasing acceleration.
The graph D, however is a straight line parallel to the time axis. The speed of the body has the same value at all times. Therefore, Graph D is the graph which shows the motion of a body with constant speed.
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Answer:
KE + PE = KE + PE
Explanation:
In a closed system, the mechanical energy of the system is constant.
Mechanical energy is given by the sum of kinetic energy and potential energy; mathematically:
U = KE + PE
where
KE is the kinetic energy
PE is the potential energy
This means that if we consider two situations, one at the beginning and one at the end, the value of U will not change if the system is closed; this means that the sum KE + PE will remain the same, so we can write:
KE + PE = KE + PE
smartphones break due to forces acting on the material.
force causes material to deform.
material is often brittle and cracks due to a limit on hardness / electricity in screens.
newton's 2nd law states
force = DV / DT
to help phones we must slow down change in momentum to reduce the force
thus we must use some form of damping in the form of a case .
the case is typically able to deform and rubber is elastic converting the kinetic energy to heat as it deforms instead of transferring it through the screen.
therefore the change in velocity occurs over a longer time. therefore the impulse decreases
