If water in one flask and castor oil in other are violently shaken and kept on a table, which will come to rest earlier

Two identical water bottles one empty and the other filled with water are allowed to roll down an inclined plane. Which one of them reaches the bottom first ? Explain your answer.

A person invites a group of 10 friends at dinner and sits (i) 5 on a round table and 5 on other round table (ii) 4 on one round table 6 on other round table . Find no. of ways in each case in which he can arrange the guest?

A ball of mass m moving with a velocity v along X-axis, strikes another ball of mass 2m kept at rest. The first ball comes to rest after collision and the other breaks into two equal pieces. One of the pieces starts moving along Y-axis with a speed v_1 . what will be the velocity of the other piece?

A number of 18 guests have to be seated, half on each side of a long table. Four particular guests desire to sit on one particular side and three others on the other side. Determine the number of ways in which the sitting arrangements can be made.

Two identical rods of copper and iron are coated with wax uniformly. When one end of each is kept at temperature of boiling water, the length upto which wax melts are 8.4cm and 4.2cm respectively. If thermal conductivity of copper is 0.92, then thermal conductivity of iron is