i$)$ The only two forces acting on a body have magnitudes of $20$ N and $40$ N and directions that differ by $80.$ The resulting acceleration has a magnitude of $10\frac{m}{s^2}.$ Find the mass of the body.

$(10$ marks$)$

ii$)$ After a completely inelastic collision, two objects of the same mass and same initial speed move away together at a third of their initial speed. Find the angle between the initial velocities of the objects.

$(15$ marks$)$

i$)$ A $125$ cm length of string has mass $2\mathrm{.}00$ g and tension $7\mathrm{.}00$ N $.($a$)$ Calculate the wave speed for this string. $($b$)$ Find the lowest resonant frequency of this string.

$(10$ marks$)$

ii$)$ In a dorable$-$slit arrangement the slits are separated by a distance equal to $100$ times the wavelength of the light passing through the slits. $($a$)$ Calculate the angular separation in radians

i$)$ A $125$ cm length of string has mass $2\mathrm{.}00$ g and tension $7\mathrm{.}00$ N $.($a$)$ Calculate the wave speed for this string. $($b$)$ Find the lowest resonant frequency of this string.

$(10$ marks$)$

ii$)$ In a dorable$-$slit arrangement the slits are separated by a distance equal to $100$ times the wavelength of the light passing through the slits. $($a$)$ Calculate the angular separation in radians