ENGINEERING MECHANICS QUIZ

The static friction

Always acts in a direction, opposite to that in which the body tends to move

Is independent of the area of contact, between the two surfaces

All of these

Bears a constant ratio to the normal reaction between the two surfaces

TRUE ANSWER : ?
YOUR ANSWER : ?

If ‘P’ is the force acting on the body, ‘m’ is the mass of the body and ‘a’ is the acceleration of the body, then according to Newton's second law of motion,

P + m.a = 0

P × m.a = 0

P/m.a = 0

P - m.a = 0

TRUE ANSWER : ?
YOUR ANSWER : ?

The moment of inertia of a sphere of mass 'm' and radius 'r', about an axis tangential to it, is

2mr²/5

2mr²/3

7mr²/5

7mr²/3

TRUE ANSWER : ?
YOUR ANSWER : ?

The motion of a wheel of a car is

Purely translation

None of the listed here

Purely rotational

Combined translation and rotational

TRUE ANSWER : ?
YOUR ANSWER : ?

The efficiency of a lifting machine is the ratio of

Output to the input

Work done by the machine to the work done on the machine

Mechanical advantage to the velocity ratio

All of these

TRUE ANSWER : ?
YOUR ANSWER : ?

A lead ball with a certain velocity is made to strike a wall, it falls down, but rubber ball of same mass and with same velocity strikes the same wall, it rebounds. Select the correct reason from the following:

The change in momentum suffered by rubber ball is more than the lead ball

Both the balls undergo an equal change in momentum

None of these

The change in momentum suffered by rubber ball is less than the lead ball

TRUE ANSWER : ?
YOUR ANSWER : ?

If u₁ and u₂ are the velocities of two moving bodies in the same direction before impact and v₁ and v₂ are their velocities after impact, then coefficient of restitution is given by

(v₂ - v₁)/(u₁ - u₂)

(u₁ - u₂)/(v₁ - v₂)

(u₂ + u₁)/(v₂ + v₁)

(v₁ - v₂)/(u₁ - u₂)

TRUE ANSWER : ?
YOUR ANSWER : ?

When the lift is moving upwards with some acceleration, the pressure exerted by a man is __________ to its acceleration.

None of these

Cube root

Directly proportional

Inversely proportional

TRUE ANSWER : ?
YOUR ANSWER : ?

The maximum efficiency of a screw jack is

(1 - tanφ)/(1 + tanφ)

(1 - sinφ)/(1 + sinφ)

(1 + sinφ)/(1 - sinφ)

(1 + tanφ)/(1 - tanφ)

TRUE ANSWER : ?
YOUR ANSWER : ?

The periodic time of a particle with simple harmonic motion is _________ proportional to the angular velocity.

Directly

Inversely

None of these

Square root

TRUE ANSWER : ?
YOUR ANSWER : ?

↑