Question

A child swinging on a swing set reaches the lowest point in her swing.Then:.
(a)The tension in the rope is equal to her weight
(b)The tension in the rope supplies a centrifugal force
(c)Her kinetic energy is at maximum
(d)Her tangential acceleration equals gravity
(e)Her angular velocity is minimum

Answer 1

Hint:In order to solve this question, it is to be noted that All the gravitational potential energy at the top of the child's swing pathway is converted into kinetic energy at the bottom of her swing pathway.
According to conservation of total energy,
\[E=U+K=constant\], where $E$ is the total energy, $U$ is the potential energy and $K$ is the kinetic energy.
At the lowest point, the potential energy of the child is minimum, thus her kinetic energy must be maximum at that point.

Thus, the answer to this question is option (c).

Additional Information: The law of conservation of energy is a very important law in thermodynamics study in Physics. According to it energy can neither be created nor be destroyed. But we may transform it from one form to another. If we take all forms of energy into consideration, then the total energy of an isolated system always remains constant. All kinds of energy follow the law of conservation of energy.

Note:While solving this question, we should be aware of the different types of energy i.e. potential energy and kinetic energy. In order to calculate total energy, we have to add both together potential as well as kinetic energy.