A projectile fired form the ground follows a parabolic path. The speed of the projectile is minimum at the top of its path.

2. The number of vectors of unit length perpendicular to vectors

**a**= (1,1,0) and

**b**= (0,1,1) is

a. three

b. two

c. one

d. infinite

e. none of these

3. Let z1 and z2 be complex numbers such that z1≠z2 and |z1| = |z2|. If z1 has positive real part and z2 has negative imaginary part, then (z1+z2)/(z1-z2) may be

a. real and positive

b. zero

c. real and negative

d. purely imaginary

e. none of these

4. If two compounds have the same empirical formula but different molecular formulae they must have ------

a. different percentage composition

b. different molecular weight

c. same viscosity

d. same vapour density