The upper half of an inclined plane with inclination $\phi$ is perfectly smooth, while the  lower half is rough. $A$ body starting from rest at the top will again come to rest at the  bottom, if the coefficient of friction for the lower half is given by-

  • A

    $2 \sin \phi$

  • B

    $2 \cos \phi$

  • C

    $2 \tan \phi$

  • D

    $ \tan \phi$

Similar Questions

In an elastic collision of two billiard balls, which of the following quantities remain conserved during the short time of collision of the balls ? (i.e. when they are in contact)

$(a)$ Kinetic energy.

$(b)$ Total linear momentum.

Give reason for your answer in each case.

Two particles, $1$ and $2$ , each of mass $m$, are connected by a massless spring, and are on a horizontal frictionless plane, as shown in the figure. Initially, the two particles, with their center of mass at $x_0$, are oscillating with amplitude a and angular frequency $\omega$. Thus, their positions at time $t$ are given by $x_1(t)=\left(x_0+d\right)+a \sin \omega t$ and $x_2(t)=\left(x_0-d\right)-$ $a$ sin $\omega t$, respectively, where $d>2 a$. Particle $3$ of mass $m$ moves towards this system with speed $u_0=a \omega / 2$, and undergoes instantaneous elastic collision with particle 2 , at time $t_0$. Finally, particles $1$ and $2$ acquire a center of mass speed $v_{ cm }$ and oscillate with amplitude $b$ and the same angular frequency. . . . .

($1$) If the collision occurs at time $t_0=0$, the value of $v_{ cm } /(a \omega)$ will be

($2$) If the collision occurs at time $t_0=\pi /(2 \omega)$, then the value of $4 b^2 / a^2$ will be

Give the answer or quetion ($1$) and ($2$)

  • [IIT 2024]

A ball is allowed to fall from a height of $10 \,m$. If there is $40 \%$ loss of energy due to impact, then after one impact ball will go up by ........ $m$

A particle of mass $m$ moving horizontally with $v_0$ strikes $a$ smooth wedge of mass $M$, as shown in figure. After collision, the ball starts moving up the inclined face of the wedge and rises to $a$ height $h$. Choose the correct statement related to the wedge $M$

$A$ small sphere is moving at $a$ constant speed in $a$ vertical circle. Below is a list of quantities that could be used to describe some aspect of the motion of the sphere.

$I$ - kinetic energy

$II$- gravitational potential energy

$III$ - momentum

Which of these quantities will change as this sphere moves around the circle?