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WorksheetsMechanical Quiz 14 June
Total questions: 20
Worksheet time: 10mins
Which gear type produces the quietest operation due to gradual tooth engagement?
Spur gear
Helical gear
Bevel gear
Worm gear
Two gears of the same module are in mesh. If one gear has double the number of teeth, what happens to the speed?
Doubled
Halved
Same
Cannot determine without pressure angle
Which of the following statements about worm gears is true?
They are used for parallel shafts
They always provide a speed increase
They allow self-locking under certain conditions
They produce less friction than spur gears
Which of the following gear train types is best suited for achieving a large speed reduction in a compact space, and can have both input and output shafts on the same axis?
Simple gear train
Compound gear train
Reverted gear train
Epicyclic (planetary) gear train
A spur gear pair with involute teeth is transmitting power under standard conditions. If the pressure angle ϕ is increased from 20 to 25 degree while keeping the module and number of teeth constant, which of the following is most correct regarding the implications on gear performance?
The base circle radius increases, and the gear becomes more compact, reducing backlash.
The contact ratio decreases, resulting in increased noise and reduced smoothness.
The radial force component decreases, reducing bearing loads but increasing sliding.
The tooth becomes thinner, increasing the load-carrying capacity and durability.
In belt drives, what causes “creep”?
Uneven belt tension due to elongation
Excessive torque
Slipping between belt and pulley
Lack of lubrication
In belt drives, which of the following would increase slip?
Increased belt tension
Using a V-belt instead of a flat belt
Decreased pulley diameter
High coefficient of friction between belt and pulley
In a belt drive system, the driver pulley has a diameter of D1=500 and the follower pulley has a diameter of D2=250 mm. If the driver rotates at N1=300 RPM, and the belt is crossed, which of the following correctly gives the velocity ratio and direction of rotation of the driven pulley?
Velocity ratio : N1/N2=D1/D2, rotation is same as driver
Velocity ratio: N1/N2=D2/D1, rotation is same as driver
Velocity ratio: N1/N2=D2/D1, rotation is opposite to driver
Velocity ratio: N1/N2=D1/D2, rotation is opposite to driver
Compared to belt drives, which of the following is a true advantage of chain drives in power transmission systems?
They provide negative (slip) drive and non-constant velocity ratio
They provide negative (slip) drive and constant velocity ratio
They provide positive (non-slip) drive and non-constant velocity ratio
They provide positive (non-slip) drive and constant velocity ratio
Which of the following best describes the main advantage of a Continuously Variable Transmission (CVT) system compared to traditional gear-based transmissions?
It increases fuel consumption due to constant high RPM operation
It allows seamless variation of gear ratio, optimizing engine performance
It uses fixed gear ratios to provide high torque output
It is limited to use only in low-speed, low-power applications
Which of the following changes would most effectively reduce the risk of a four-wheeled robot tipping over while turning sharply?
Increasing the height of the center of mass
Decreasing the track width of the robot
Adding weight to the top of the robot
Lowering the center of mass closer to the ground
What is the primary advantage of using Mecanum wheels in a mobile robot compared to standard wheels?
Increased traction on uneven terrain
Ability to move only in forward and backward directions
Omnidirectional movement without changing the robot's orientation
Higher top speed due to reduced rolling resistance
What makes omni wheels different from standard wheels in terms of movement capability?
They have higher friction, allowing better acceleration
They enable sideways movement by rotating freely along multiple axes
They are designed only for off-road terrains
They have internal motors for multidirectional control
What is the main function of a caster wheel in a mobile robot or trolley system?
To provide powered omnidirectional movement
To support heavy loads while enabling pivoting for steering
To act as a suspension element for shock absorption
To increase the robot's speed by reducing friction
What does the KV rating of a BLDC motor represent?
The voltage required to rotate the motor at 1 RPM
The torque produced per volt applied to the motor
The number of RPM the motor produces per volt applied (under no load)
The current drawn by the motor per volt applied
In a sensorless BLDC motor, how is the rotor position typically determined for commutation?
Using optical encoders mounted on the shaft
By measuring back EMF in the undriven phase windings
By detecting changes in shaft current using Hall sensors
By integrating the supply voltage over time
Which of the following best explains how a servo motor maintains precise control of position?
It runs continuously at a fixed speed set by voltage input
It adjusts its position based on feedback from an internal sensor
It uses an open-loop system with fixed timing pulses
It changes direction only when the power polarity is reversed
Which of the following statements best describes the operation of a stepper motor?
It continuously rotates at a speed proportional to the input voltage
It uses an encoder to correct position based on feedback
It rotates in discrete steps controlled by pulses sent to the windings
It requires a variable frequency drive (VFD) for precise control
A motor is rated at 300 W mechanical output and operates at a speed of 1500 RPM. Assuming no losses, what is the torque output of the motor?
0.19 Nm
1.91 Nm
3.14 Nm
19.1 Nm
Which of the following features in SolidWorks would be most appropriate to create a part with a helical groove (such as a thread on a bolt or a screw)?
Extruded Cut
Revolve
Sweep with a Helix path
Fillet
