Engineering Mechanics
Which of the following statement is incorrect?

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
A machine whose efficiency is 100% is known as an ideal machine
The ratio of the limiting friction to the normal reaction is called coefficient of friction

ANSWER DOWNLOAD EXAMIANS APP

Engineering Mechanics
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 less than the lead ball
None of these
The change in momentum suffered by rubber ball is more than the lead ball
Both the balls undergo an equal change in momentum

ANSWER DOWNLOAD EXAMIANS APP