MCQ
For circular motion, if ${\vec a_t},\,{\vec a_c},\,\vec r$ and $\vec v$ are tangential acceleration, centripetal acceleration, radius vector and velocitym respectively, then find the wrong relation
  • A
    ${\vec a_t}.{\vec a_c} = 0$
  • B
    ${\vec a_t}.\vec v$ may be positive or negative
  • ${\vec a_c}.\vec v$ may be positive or negative
  • D
    ${\vec a_c}.\vec v = 0$

Answer

Correct option: C.
${\vec a_c}.\vec v$ may be positive or negative
c
$\overrightarrow{\mathrm{a}}_{\mathrm{t}} \cdot \overrightarrow{\mathrm{a}}_{\mathrm{c}}=0 \quad$ as $\theta=90^{\circ}$

$\overrightarrow{\mathrm{a}}_{\mathrm{c}} \cdot \overrightarrow{\mathrm{v}}=0 \quad$ as $\theta=90^{\circ}$

$\overrightarrow{\mathrm{a}}_{\mathrm{t}} \cdot \overrightarrow{\mathrm{v}}$ may be $+\mathrm{ve}$ or $-\mathrm{ve}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

A diatomic gas follows equation $PV^m =$ constant, during a process. What should be the value of $m$ such that its molar heat capacity during process $= R$
A spherical ball is dropped in a long column of a viscous liquid. The speed of the ball as a function of time may be best represented by the graph:
  1. A
  2. B
  3. C
  4. D

Velocity-time graph for a car is semicircle as shown here. Which of the following is correct :
A projectile fired with initial velocity $u$ at some angle $\theta $ has a range $R$. If the initial velocity be doubled at the same angle of projection, then the range will be
A fully loaded boeing aircraft has a mass of $5.4 \times 10^5\,kg$. Its total wing area is $500\,m ^2$. It is in level flight with a speed of $1080\,km / h$. If the density of air $\rho$ is $1.2\,kg\,m ^{-3}$, the fractional increase in the speed of the air on the upper surface of the wing relative to the lower surface in percentage will be $\left( g =10\,m / s ^2\right)$
Two particles of equal mass go around a circle of radius R under the action of their mutual gravitational attraction. The speed v of each particle is:
The time period of mass suspended from a spring is T. If the spring is cut into four equal parts and the same mass is suspended from one of the parts, then the new time period will be:
The physical quantity $'$Energy Density$'$ has same dimensional formula as
A man squatting on the ground gets straight up and stand. The force of reaction of ground on the man during the process is:
If $v$ is the speed of sound in air then the shortest length of the closed pipe which resonates to a frequency $n$