**Answer is:**

### Twice the rotating frequency

**Explanation:**

.In slider crank mechanism, secondary forces fluctuate at twice the rotating frequency.

**Answer is:**

### Bernoulli's principle

**Explanation:**

Venturimeter works on the basis of Bernoulli's principle.

The Bernoulli's equation states that For a perfect incompressible liquid, flowing in a continuous stream, the total energy of a particle remains the same, while the particle moves from one point to another.

The Bernoulli's equation is applied to venturimeter, orifice meter and pitot tube.

**Answer is:**

### 1 and 2

**Explanation:**

In thermodynamics, a process in Quasi-static process and Reversible process undergoes a succession of equilibrium states.

**Answer is:**

### 2 and 3

**Explanation:**

In thermodynamics

Work is path dependent function

Work is area under the curve in a PV diagram

**Answer is:**

### 2 and 3

**Explanation:**

Heat and Work are not completely interchangeable forms of energy

Work can be converted completely into heat