Velocity and Acceleration

Как это проверяет настоящий экзамен

Задания из настоящих экзаменов CSCA по этому понятию. Решите их сами, прежде чем открывать ответ.

1. CSCA Physics December 2025 Past Paper
   As shown in the figure, an object moves from point $A$ through point $B$ to point $C$ along two semicircles with radius $R = 6 \mathrm {~m}$, taking a time of $t = 4 \mathrm {~s}$. The magnitude of its average velocity is ().
   • A．$6 \mathrm {~m} / \mathrm { s }$
   • B．$12 \mathrm {~m} / \mathrm { s }$
   • C．$6 \pi \mathrm {~m} / \mathrm { s }$
   • D．$3 \pi \mathrm {~m} / \mathrm { s }$
   Показать ответ и решение

   Ответ: A

   1 Displacement is the straight line from A to C. The two semicircles each have diameter $2 R = 12 \mathrm {~m}$, so the displacement is $x = 4 R = 24 \mathrm {~m}$. 2 Average velocity $= x / t = 24 \mathrm {~m} / 4 \mathrm {~s} = 6 \mathrm {~m} / \mathrm { s }$, option A. 3 Note: the path length is $2 \pi R = 12 \pi \mathrm {~m}$, so $3 \pi \mathrm {~m} / \mathrm { s }$ (option D) is the average speed, not the average velocity.
   Открыть в полном варианте: CSCA Physics December 2025 Past Paper
2. CSCA Physics March 2026 Past Paper
   The x-t graph for a toy car in linear motion is shown. Which statement is correct?
   • A．Displacement from $0 - 4 \mathrm {~s}$ is 8 m
   • B．Velocity from $0 - 4 \mathrm {~s}$ is $1.0 \mathrm {~m} / \mathrm { s }$
   • C．Average velocity from $0 - 5 \mathrm {~s}$ is $0.8 \mathrm {~m} / \mathrm { s }$
   • D．Velocity from $4 - 5 \mathrm {~s}$ is $0.8 \mathrm {~m} / \mathrm { s }$
   Показать ответ и решение

   Ответ: B

   From graph: $0 - 4 \mathrm {~s} , x$ goes from 0 to 4 m linearly. A: displacement is 4 m , not 8 . $B : v = 4 / 4 = 1.0 \mathrm {~m} / \mathrm { s }$, correct. C: at 5 s position returns to 0 , average velocity $= 0 / 5 = 0$. D: $4 - 5 \mathrm {~s}$, displacement $= 4 \mathrm {~m}$ in 1 s , speed $= 4 \mathrm {~m} / \mathrm { s }$. Answer: B.
   Решить весь CSCA Physics March 2026 Past Paper — на время и с оценкой
3. CSCA Physics April 2026 Past Paper
   As shown in the figure, an object travels along a path consisting of two semicircles end-to-end (each of radius 4 m ) from $A$ through $B$ to $C$. Points $A , B , C$ are collinear along the east-west direction. The travel takes 2 s . The magnitude of the average velocity is
   • A．$4 \mathrm {~m} / \mathrm { s }$
   • B．$0 \mathrm {~m} / \mathrm { s }$
   • C．$2 \mathrm {~m} / \mathrm { s }$
   • D．$8 \mathrm {~m} / \mathrm { s }$
   Показать ответ и решение

   Ответ: D

   Each semicircle has diameter $2 R = 8 \mathrm {~m}$, so $| A B | = | B C | = 8 \mathrm {~m}$. Because $A$, $B , C$ are collinear, the total displacement is $| A C | = 16 \mathrm {~m}$. Average velocity $= \frac { | A C | } { t } = \frac { 16 } { 2 } = 8 \mathrm {~m} / \mathrm { s }$.
   Решить весь CSCA Physics April 2026 Past Paper — на время и с оценкой