Suppose that a mothball loses volume by evaporation at a rate proportional to its instantaneous area. If the diameter of the ball decreases from 2cm to 1cm in 3 months, how long will it take until the ball has practically gone?

A sound wave has a frequency of 2 kHz and wavelength 35 cm . How long will it take to travel 1.5 km ?

A stone is dropped from certain height above the ground. After 5 s a ball passes trhough a pane of glass held horizontally and instantaneously loses 20% of its velocity. If the ball takes 2 more seconds to reach the ground the height of the glass above the ground is

There are three taps of diameters 1cm, 4/3 cm and 2 cm , respectively . The ratio of the water flowing through them is equal to the ratio of the square of their diameters . The biggest tap can fill the tank alone in 61 min . If all taps are opened simulataneously ,how long will the tank take to be filled ?

A spherical snow ball is melting so that its volume is decreasing at the rate of 8 cc/sec. Find the rate at which its radius is decreasing when it is 2 cm.

The volume of the cylindrical trunk of a tree is proportional to the cube of its diameter and the diameter increases uniformly from year to year,prove that the rate of increase in the volume when the diameter is equal to 90cm is 25 xx the ratewhen it is 18cm.

A cylindrical pipe has inner diameter of 4cm and water flows through it at the rate of 20 metre per minute.How long would it take to fill a conical tank of radius 40cm and depth 72cm?

There are three taps of diameter 1 cm, 4/3 cm and 2 cm, respectively. The ratio of the water flowing through them is equal to the ratio of the square of their diameters. The biggest tap can fill the tank alone in 61 min. If all the taps are opened simultaneously, how long will the tank take to be filled?