The velocity of sound in air at 15°C is 340ms\(^{-1}\). Calculate the velocity at 47\(^o\)C

Which of the current-voltage characteristics shown above is that exhibited an ohmic conductor? 

 A 500N box rests on a horizontal floor. A constant horizontal force is exerted on the box so that it moves through 8m. If the coefficient of kinetic  friction between the floor and the box is 0.22, calculate the workdone on the box
 

The diagram illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F, and the acceleration of free fall is g. The normal force on the ball is?

The diagram above illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F and the acceleration of free fall is g. The net force on the ball along the plank is?