Physics Questions and Answers

The fundamental frequency $(f_{0})$ = $\frac{v}{2l}$

$f_{0} = 150Hz; l =400cm = 4m$

$150 = \frac{v}{2\times 4}$

$v = 150 \times 8 = 1200ms^{-1}$

Given $K_{1}$ = $\frac{mv^{2}}{2}$.

When v is halved, we have

$K_{2}$ = $\frac{m\times (\frac{v}{2})^{2}}{2}$

= $\frac{K_{1}}{4}$

Hence, the initial kinetic energy is quartered.

The velocity ratio and therefore, the mechanical advantage of an inclined plane system increases as $\theta$ decreases and vice-versa.

The ideal transformer (either step-up or step-down) works with the equation:

$\frac{V_{s}}{V_{p}} = \frac{N_{s}}{N_{p}} = \frac{I_{p}}{I_{s}}$

where $V_{s}$ and $V_{p}$ are the voltages applied to the secondary and the primary respectively

$N_{s}$ and $N_{p}$ are the number of turns on the secondary and primary coils respectively

$I_{p}$ and $I_{s}$ are the currents flowing in the primary and secondary coils respectively.

$\frac{V_{s}}{100} = \frac{200}{100}$

$V_{s} = \frac{200\times 100}{100} = 200V$

$F= \frac{Gm_{1}m_{2}}{r^{2}}$

$m_{1} = 100kg$

$m_{2} = 20kg; r =1.2m$

$G= 6.67\times 10^{-11}$

$F = \frac{6.67\times 10^{-11}\times 100\times 20}{(1.2)^{2}} = 9.26\times 10^{-8}$

The acceleration of each object is inversely proportional to the mass, the lighter object will move a bit faster, hence. the force will act in the direction of Q.