Two pulleys of radii r1 and r2 and at distance x apart are connected by means of an open belt drive. The length of the belt is
A. $$\pi \left( {{{\text{r}}_1} + {{\text{r}}_2}} \right) + \frac{{{{\left( {{{\text{r}}_1} + {{\text{r}}_2}} \right)}^2}}}{{\text{x}}} + 2{\text{x}}$$
B. $$\pi \left( {{{\text{r}}_1} + {{\text{r}}_2}} \right) + \frac{{{{\left( {{{\text{r}}_1} - {{\text{r}}_2}} \right)}^2}}}{{\text{x}}} + 2{\text{x}}$$
C. $$\pi \left( {{{\text{r}}_1} - {{\text{r}}_2}} \right) + \frac{{{{\left( {{{\text{r}}_1} - {{\text{r}}_2}} \right)}^2}}}{{\text{x}}} + 2{\text{x}}$$
D. $$\pi \left( {{{\text{r}}_1} - {{\text{r}}_2}} \right) + \frac{{{{\left( {{{\text{r}}_1} + {{\text{r}}_2}} \right)}^2}}}{{\text{x}}} + 2{\text{x}}$$
Answer: Option B
In considering friction of a V-thread, the virtual coefficient of friction (μ1) is given by
A. μ1 = μsinβ
B. μ1 = μcosβ
C. $${\mu _1} = \frac{\mu }{{\sin \beta }}$$
D. $${\mu _1} = \frac{\mu }{{\cos \beta }}$$
The lower pairs are _________ pairs.
A. Self-closed
B. Force-closed
C. Friction closed
D. None of these
In a coupling rod of a locomotive, each of the four pairs is a ________ pair.
A. Sliding
B. Turning
C. Rolling
D. Screw
A kinematic chain is known as a mechanism when
A. None of the links is fixed
B. One of the links is fixed
C. Two of the links are fixed
D. None of these
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