# Recent questions tagged theory-of-machines

0 votes
0 answers
A four bar mechanism is shown below. For the mechanism to be a crank-rocker mechanism, the length of the link $PQ$ can be $80\: mm$ $200\: mm$ $300\: mm$ $350\: mm$
0 votes
0 answers
A helical gear with $20^{\circ}$ pressure angle and $30^{\circ}$ helix angle mounted at the mid-span of a shaft that is supported between two bearings at the ends. The nature of the stresses induced in the shaft is normal stress due to bending only ... bending in two planes and axial loading; shear stress due to torsion normal stress due to bending in two planes; shear stress due to torsion
0 votes
0 answers
A flywheel is attached to an engine to keep its rotational speed between $100\: rad/s$ and $110\: rad/s$. If the energy fluctuation in the flywheel between these two speeds is $1.05\: kJ$ then the moment of inertia of the flywheel is____________$kg \cdot m^{2}$ (rounded off to $2$ decimal places).
0 votes
0 answers
A rigid triangular body, PQR, with sides of equal length of $1$ unit moves on a flat plane. At the instant shown, edge QR is parallel to the $x$-axis, and the body moves such that velocities of points P and R are $V_P$ and $V_R$, in the $x$ and $y$ directions, respectively. The magnitude of the angular velocity of the body is $2V_R$ $2V_P$ $V_R/\sqrt{3}$ $V_P/\sqrt{3}$
0 votes
0 answers
The crank of a slider-crank mechanism rotates counter-clockwise (CCW) with a constant angular velocity $\omega$, as shown. Assume the length of the crank to be $r$. Using exact analysis, the acceleration of the slider in the $y$-direction, at the instant shown, where the crank is parallel to $x$-axis, is given by $- \omega ^2r$ $2 \omega ^2r$ $\omega ^2r$ $-2 \omega ^2r$
0 votes
1 answer
A four bar mechanism is shown in the figure. The link numbers are mentioned near the links. Input link $2$ is rotating anticlockwise with a constant angular speed $\omega_2$. Length of different links are: $O_2 O_4=O_2A=L,$$AB=O_4B=\sqrt{2}L$ The magnitude of the angular ... $90^{\circ}$ with $O_2O_4$ as shown. The ratio $\frac{\omega_4}{\omega_2}$ is _________ (round off to two decimal places).
0 votes
0 answers
A block of mass $10$ kg rests on a horizontal floor. The acceleration due to gravity is $9.81 \: m/s^2$. The coefficient of static friction between the floor and the block is $0.2$. A horizontal force of $10$ N is applied on the block as shown in the figure. The magnitude of force of friction (in N) on the block is _____
0 votes
0 answers
A car having weight $W$ is moving in the direction as shown in the figure. The center of gravity (CG) of the car is located at height $h$ from the ground, midway between the front and rear wheels. The distance between front and rear wheel is $l$. The acceleration of the car is $a$, and acceleration ... $R_f=R_r = \dfrac{W}{2}+\dfrac{W}{g} \bigg( \dfrac{h}{l} \bigg) a$
0 votes
0 answers
In the mechanism given below, if the angular velocity of the eccentric circular disc is $1$ rad/s, the angular velocity (rad/s) of the follower link for the instant shown in the figure is $0.05$ $0.1$ $5.0$ $10.0$
0 votes
0 answers
A solid disc of radius $r$ rolls without slipping on a horizontal floor with angular velocity $\omega$ and angular acceleration $\alpha$. The magnitude of the acceleration of the point of contract on the disc is $zero$ $r \alpha$ $\sqrt{(r \alpha)^2 + (r \omega^2)^2}$ $r \omega^2$
0 votes
0 answers
The following are the data for the two crossed helical gears used for speed reduction: Gear I: Pitch circle diameter in the plane of rotation $80$ mm and helix angle $30^{\circ}$ Gear II: Pitch circle diameter in the plane of rotation $120$ mm and helix angle $22.5^{\circ}$ If the input speed is $1440$ rpm, the output speed in rpm is $1200$ $900$ $875$ $720$
0 votes
0 answers
A slider crank mechanism is shown in the figure. At some instant, the crank angle is 45$^{\circ}$ and force of $40$ N is acting towards the left on the slider. The length of the crank is $30$ mm and the connecting rod is $70$ mm. Ignoring ... and inertial forces, the magnitude of the crankshaft torque (in Nm) needed to keep the mechanism in equilibrium is ______ (correct to two decimal places)
0 votes
0 answers
An epicyclic gear train is shown in the figure below. The number of teeth on the gears A, B and D are $20$, $30$ and $20$, respectively. Gear C has $80$ teeth on the inner surface and $100$ teeth on the outer surface. If the carrier arm AB is fixed and the sun gear A rotates at $300$ rpm in the clockwise direction, then the rpm of D in the clockwise direction is $240$ $-240$ $375$ $-375$
0 votes
0 answers
A four bar mechanism is made up of links of length $100$, $200$, $300$ and $350$ mm. If the $350$ mm link is fixed, the number of links that can rotate fully is _________
0 votes
0 answers
A gear train shown in the figure consists of gears $P, Q, R,$ and $S$. Gear $Q$ and gear $R$ are mounted on the same shaft. All the gears are mounted on parallel shafts and the number of teeth of $P, Q, R$ and $S$ are $24, 45, 30,$ and $80$, respectively. Gear $P$ is rotating at $400$ rpm. The speed (in rpm) of the gear $S$ is __________.
0 votes
0 answers
Two disks $A$ and $B$ with identical mass $(m)$ and radius $(R)$ are initially at rest. They roll down from the top of identical inclined planes without slipping. Disk $A$ has all of its mass concentrated at the rim, while Disk $B$ has its mass uniformly distributed. At the bottom of the plane, the ... the centre of disk $B$ is $\sqrt{\dfrac{3}{4}} \\$ $\sqrt{\dfrac{3}{2}} \\$ $1 \\$ $\sqrt{2}$
0 votes
0 answers
In an epicyclic gear train, shown in the figure, the outer ring gear is fixed, while the sun gear rotates counterclockwise at $100$ rpm. Let the number of teeth on the sun, planet and outer gears to be $50, 25$ and $100$, respectively. The ratio of magnitudes of angular velocity of the planet gear to the angular velocity of the carrier arm is ________.
0 votes
0 answers
A rigid rod $(AB)$ of length $L=\sqrt{2} \: m$ is undergoing translational as well as rotational motion in the $x-y$ plane (see the figure). The point $A$ has the velocity $V_1=\hat{i}+2\hat{j} \: m/s$. The end B is constrained to move only along the $x$ direction. The magnitude of the velocity $V_2$ (in $m/s$) at the end B is __________
0 votes
0 answers
A circular disc of radius $100 \: mm$ and mass $1 \: kg$, initially at rest at position $A$, rolls without slipping down a curved path as shown in figure. The speed $v$ of the disc when it reaches position $B$ is _________ $m/s$. Acceleration due to gravity $g = 10 \: m/s^2$.
0 votes
0 answers
In the gear train shown, gear $3$ is carried on arm $5$. Gear $3$ meshes with gear $2$ and gear $4$. The number of teeth on gear $2$, $3$, and $4$ are $60$, $20$, and $100$, respectively. If gear $2$ is fixed and gear $4$ rotates with ... in the counterclockwise direction, the angular speed of arm $5$ (in $rpm$) is $166.7$ counterclockwise $166.7$ clockwise $62.5$ counterclockwise $62.5$ clockwise
0 votes
0 answers
A car is moving on a curved horizontal road of radius $100$ $m$ with a speed of $20$ $m/s$. The rotating masses of the engine have an angular speed of $100$ $rad/s$ in clockwise direction when viewed from the front of the car. The combined moment of inertia of the rotating masses is $10$ $kg$-$m^2$. The magnitude of the gyroscopic moment (in $N$-$m$) is __________
0 votes
0 answers
A point mass $M$ is released from rest and slides down a spherical bowl (of radius $R$) from a height $H$ as shown in the figure below. The surface of the bowl is smooth (no friction). The velocity of the mass at the bottom of the bowl is $\sqrt{gH}$ $\sqrt{2gR}$ $\sqrt{2gH}$ $0$
0 votes
0 answers
The number of degrees of freedom of the linkage shown in the figure is -$3$ $0$ $1$ $2$
0 votes
0 answers
Figure shows a wheel rotating about $O_2$. Two points $A$ and $B$ located along the radius of wheel have speeds of $80$ $m/s$ and $140$ $m/s$ respectively. The distance between the points $A$ and $B$ is $300$ $mm$. The diameter of the wheel (in $mm$) is ________
0 votes
0 answers
A gear train is made up of five spur gears as shown in the figure. Gear $2$ is driver and gear $6$ is driven member. $N_2$, $N_3$, $N_4$, $N_5$ and $N_6$ represent number of teeth on gears $2$, $3$, $4$, $5$, and $6$ respectively. The gear(s) which act(s) as idler(s) is/are Only $3$ Only $4$ Only $5$ Both $3$ and $5$
0 votes
0 answers
For the same material and the mass, which of the following configurations of flywheel will have maximum mass moment of inertia about the axis of rotation OO’ passing through the center of gravity.
0 votes
0 answers
The number of degrees of freedom of the planetary gear train shown in the figure is $0$ $1$ $2$ $3$
0 votes
0 answers
A pinion with radius $r_1$, and inertia $I_1$ is driving a gear with radius $r_2$ and inertia $I_2$. Torque $\tau _1$ is applied on pinion. The following are free body diagrams of pinion and gear showing important forces ($F_1$ and $F_2$) of interaction. Which of the following relations ... $F_2=I_2\dfrac{1}{r_2}\ddot{\theta _1};$
0 votes
0 answers
Torque and angular speed data over one cycle for a shaft carrying a flywheel are shown in the figures. The moment of inertia (in $kg.m^2$) of the flywheel is _______
0 votes
0 answers
Which one of the following is used to convert a rotational motion into a translational motion? Bevel gears Double helical gears Worm gears Rack and pinion gears
0 votes
0 answers
A slider-crank mechanism with crank radius $60$ $mm$ and connecting rod length $240$ $mm$ is shown in figure. The crank is rotating with a uniform angular speed of $10$ $rad/s$, counter clockwise. For the given configuration, the speed (in $m/s$) of the slider is _______
0 votes
0 answers
Gear $2$ rotates at $1200$ $rpm$ in counter clockwise direction and engages with Gear $3$. Gear $3$ and Gear $4$ are mounted on the same shaft. Gear $5$ engages with Gear $4$. The numbers of teeth on Gears $2$, $3$, $4$ and $5$ are $20$ ... $5$ is $300$ $rpm$ counterclockwise $300$ $rpm$ clockwise $4800$ $rpm$ counterclockwise $4800$ $rpm$ clockwise
0 votes
0 answers
A spur pinion of pitch diameter $50$ $mm$ rotates at $200$ $rad/s$ and transmits $3 kW$ power. The pressure angle of the tooth of the pinion is $20^\circ$. Assuming that only one pair of the teeth is in contact, the total force (in newton) exerted by a tooth of the pinion on the tooth on a mating gear is _______
0 votes
0 answers
Consider a flywheel whose mass $M$ is distributed almost equally between a heavy, ring-like rim of radius $R$ and a concentric disk-like feature of radius $R/2$. Other parts of the flywheel, such as spokes, etc, have negligible mass. The best approximation for $α$, if the moment of inertia of the flywheel about its axis of rotation is expressed as $αMR^2$, is _______
0 votes
0 answers
A pair of spur gears with module $5$ $mm$ and a center distance of $450$ $mm$ is used for a speed reduction of $5:1$. The number of teeth on pinion is _______
0 votes
0 answers
For the given statements: Mating spur gear teeth is an example of higher pair A revolute joint is an example of lower pair Indicate the correct answer. Both $I$ and $II$ are false $I$ is true and $II$ is false $I$ is false and $II$ is true Both $I$ and $II$ are true
0 votes
0 answers
A compound gear train with gears $P$, $Q$, $R$ and $S$ has number of teeth $20$, $40$, $15$ and $20$, respectively. Gears $Q$ and $R$ are mounted on the same shaft as shown in the figure below. The diameter of the gear $Q$ is twice that of the gear $R$. If the module of the gear $R$ is $2$ $mm$, the center distance in $mm$ between gears $P$ and $S$ is $40$ $80$ $120$ $160$
0 votes
0 answers
A flywheel connected to a punching machine has to supply energy of $400 Nm$ while running at a mean angular speed of $20 rad/s$. If the total fluctuation of speed is not to exceed $±2%$, the mass moment of inertia of the flywheel in $kg$-$m^2$ is $25$ $50$ $100$ $125$
0 votes
0 answers
A planar closed kinematic chain is formed with rigid links $PQ$ = $2.0$ $m$, $QR$ = $3.0$ $m$, $RS$ = $2.5$ $m$ and $SP$ = $2.7$ $m$ with all revolute joints. The link to be fixed to obtain a double rocker (rockerrocker) mechanism is $PQ$ $QR$ $RS$ $SP$
0 votes
0 answers
A link $OB$ is rotating with a constant angular velocity of $2$ $rad$/$s$ in counter clockwise direction and a block is sliding radially outward on it with an uniform velocity of $0.75$ $m$/$s$ with respect to the rod, as shown in the figure below. If $OA$ = $1$ $m$, the magnitude of the absolute acceleration of the block at location $A$ in $m$/$s^2$ is $3$ $4$ $5$ $6$
To see more, click for the full list of questions or popular tags.