The graph below shows the position of a toy over time, measured using photogates.

at which of the labeled points is the car's velocity at a single moment lowest?

a. point a
b. point b
c. point c.
d. point d.

Point C.

.

is the same as the gradient of the tangent to the position-times graph at the point in question.

Draw a tangent line to the curve at each point. Measure the gradient of each tangent line. The gradient of the tangent line to the curve is smallest at point C among all four points. Therefore, the car's velocity is smallest at point C.

an ion is a charged atom or molecule. it is charged because the number of electrons do not equal the number of protons in the atom or molecule. an atom can acquire a positive charge or a negative charge depending on whether the number of electrons in an atom is greater or less then the number of protons in the atom.

the closer the planet is to the sun, the larger the gravity