None of these
20 N and 5 N
15 N and 5 N
15 N and 15 N

## Engineering Mechanics The time of flight (t) of a projectile on an upward inclined plane is(where u = Velocity of projection, α = Angle of projection, and β = Inclination of the plane with the horizontal.)

t = 2u sin (α + β)/g cos β
t = g cos β/2u sin (α + β)
t = 2u sin (α - β)/g cos β
t = g cos β/2u sin (α - β)

10 N-m
1 N-m
0.1 N-m
100 N-m

## Engineering Mechanics Which of the following statement is incorrect?

The ratio of the limiting friction to the normal reaction is called coefficient of friction
A machine whose efficiency is 100% is known as an ideal machine
The velocity ratio of a machine is the ratio of load lifted to the effort applied
A force acting in the opposite direction to the motion of the body is called force of friction

## Engineering Mechanics A ladder is resting on a smooth ground and leaning against a rough vertical wall. The force of friction will act

Towards the wall at its upper end
Away from the wall at its upper end
Upward at its upper end
Downward at its upper end

bh3/12
bh3/4
bh3/36
bh3/8