Question

A time interval begins at time 2 s and ends at time 5 s.  The duration of this time interval is   [ Select ] ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10" s.

The durations of two consecutive time intervals are given by 2 s and 5 s.  The duration of the combined time interval is     [ Select ] ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"] s.

When calculating the duration of a time interval given its initial and final times, we    [ Select ]     ["add", "subtract"]  the times.  When calculating the duration of a combined interval given the durations of its two subintervals, we    [ Select ]    ["add", "subtract"]         the times.

During a given time interval, a particle moves from position + 2 m to a position + 5 m.  The displacement during this time interval is  [ Select ] ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"] m.

A particle undergoes displacements + 2 m and + 5 m during two consecutive time intervals.  The displacement during the combined time interval is [ Select ]    ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]    m.

During a given time interval, a particle moves from position − 2 m to a position + 5 m.  The displacement during this time interval is          [ Select ]    ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]      m.

A particle undergoes displacements − 2 m and + 5 m during two consecutive time intervals.  The displacement during the combined time interval is    [ Select ]                       ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]    m.

When calculating the displacement of a particle given its initial and final positions, we       [ Select ]                       ["add", "subtract"]         the position values.  When calculating the displacement of a particle during a combined interval given the displacements during the two subintervals, we        [ Select ]                       ["add", "subtract"]         the displacements.

You should be able to answer the following two questions even if you don't know what kinetic energy is.

A particle's kinetic energy changes from 2 J to 5 J during a given time interval.  The change in the particle's kinetic energy during this time interval is                            [ Select ]                       ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]         J.

A particle's kinetic energy changes by + 2 J and + 5 J during two consecutive time intervals.  The change in the particle's kinetic energy during the combined time interval is                            [ Select ]                       ["0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "10"]         J.

Answer 1

(i) A time interval begins at time 2 s and ends at time 5 s.  

The duration of this time interval which will be given by -

$\Delta$t = t_final - t_initial

$\Delta$t = [(5 s) - (2 s)]

$\Delta$t = 3 s

(ii) The durations of two consecutive time intervals are given by 2 s and 5 s.  

The duration of the combined time interval which will be given by -

t_total = t₁ + t₂

t_total = [(2 s) + (5 s)]

t_total = 7 s

(iii) When calculating the duration of a time interval given its initial and final times, we subtract the times.

When calculating the duration of a combined interval given the durations of its two subintervals, we add the times.

(iv) During a given time interval, a particle moves from position +2 m to a position +5 m.  

The displacement during this time interval which will be given by -

$\Delta$x = x_final - x_initial

$\Delta$x = [(5 m) - (2 m)]

$\Delta$x = 3 m

(vi) During a given time interval, a particle moves from position -2 m to a position + 5 m.  

The displacement during this time interval which will be given by -

$\Delta$x = x_final - x_initial

$\Delta$x = [(5 m) - (-2 m)]

$\Delta$x = 7 m

(viii) When calculating the displacement of a particle given its initial and final positions, we subtract the position values.

When calculating the displacement of a particle during a combined interval given the displacements during the two sub intervals, we add the position values.

You should be able to answer the following two questions even, if we don't know what kinetic energy is.

(a) A particle's kinetic energy changes from 2 J to 5 J during a given time interval.  

The change in the particle's kinetic energy during this time interval which will be given by -

$\Delta$K.E = K.E_final - K.E_initial

$\Delta$K.E = [(5 J) - (2 J)]

$\Delta$K.E = 3 J