The centre of gravity of the trapezium as shown in below figure from the side is at a distance of
A). (h/3) [(b + 2a)/(b + a)]
B). (h/3) [(2b + a)/(b + a)]
C). (h/2) [(b + 2a)/(b + a)]
D). (h/2) [(2b + a)/(b + a)]
In SI units, the units of force and energy are respectively
A). Newton and watt
B). Dyne and erg
C). Newton and joule
D). kg wt and joule
In a lifting machine a weight of 5 kN is lifted through 200 mm by an effort of 0.1 kN moving through 15 m. The mechanical advantage and velocity ratio of the machine are respectively
A). 50 and 75
B). 75 and 50
C). 75 and 75
D). 50 and 50
A marble ball is rolled on a smooth floor of a room to hit a wall. If the time taken by the ball in returning to the point of projection is twice the time taken in reaching the wall, the coefficient of restitution between the ball and the wall, is
A). 0.25
B). 0.50
C). 0.75
D). 1.0
A ball is dropped from a height of 2.25 m on a smooth floor and rises to a height of 1.00 m after the bounce. The coefficient of restitution between the ball and the floor is
A). 0.33
B). 0.44
C). 0.57
D). 0.67