68) A projectile is fired at an angle θ to the vertical. Its horizontal range will be maximum when θ is

0°

30°

45°

60°

Answer is:

45°

Explanation:

Angle of projection: Angle of projection is the angle, with the horizontal,at which the projectile is projected.

A projectile is fired at an angle θ to the vertical. Its horizontal range will be maximum when θ is 45°.

A projectile is fired at an angle θ to the vertical. Its horizontal range will be maximum when θ is

Structural Engineering III MCQ with Answers

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69) Limiting force of friction is the

tangent of angle between normal-reaction and the resultant of normal reaction and limiting friction

ratio of limiting friction and normal reaction

the friction force acting when the body is just about to move

the friction force acting when the body is in motion

Answer is:

the friction force acting when the body is just about to move

70) Coulomb friction is the friction between

bodies having relative motion

two dry surfaces

two lubricated surfaces

solids and liquids

Answer is:

bodies having relative motion

71) Dynamic friction as compared to static friction is

same

less

may be less of more depending on nature of surfaces and velocity

Answer is:

less

Explanation:

Static Friction The friction experienced by a body, when it is at rest is known as static friction.

Dynamic Friction The friction experienced by a body, when it is in motion is called dynamic friction. Dynamic friction is also called as kinetic friction.

Dynamic friction always less than static friction.
The ratio of static friction to dynamic friction is always greater than one.