Question

A particle is moving along a curve . Then

• A. if its speed is constant, it has no acceleration
• B. if its speed is increasing, the acceleration of the particle is along its direction of motion
• C. The direction of its acceleration cannot be along the tangent.
• D. None of these

Answer 1

The correct option is C The direction of its acceleration cannot be along the tangent.

$\left(i\right)$ In accelerating body, $\overrightarrow{v}$ changes.
$\left(ii\right)\overrightarrow{a}=\overrightarrow{a_t}+\overrightarrow{a_R}$
$\left(iii\right)$Radial acceleration, $a_R$ can never be zero $\overrightarrow{a}=\overrightarrow{a_t}+\overrightarrow{a_R}$

Even if the motion is not circular, there is some acceleration which changes this direction of velocity, and this acceleration is not along the curve.