80 coins are placed in a st. line on the ground. The distance between any two consecutive coins is 10 metres. How far must a person travel to bring them one by one to a basket placed 10 metres behind the first coin?

Two plane mirrors are placed parallel to each other. The distance between the mirrors is 10cm. An object is placed between the mirrors at a distance of 4cm from one of them, say M_(1) . What is the distance between the first time formed at M_(1) and the second image formed at M_(2) ?

Two parallel rails of a railway track insulated from each other and with the ground are connected to a millivoltmeter. The distance between the rails is one metre. A train is traveling with a velocity of 72 km ph along the track. The reading of the millivoltmetre (in m V ) is : (Vertical component of the earth's magnetic induction is 2 xx 10^(-5) T )

In a potato race 20 potatoes are placed in a line at intervals of 4m e t e r s with first potato 24m e t r e s from the starting point. A contestant is required to bring the potatoes back to the starting place one at a time. How far would he run in bringing back all the potatoes?

In a potato race 20 potatoes are placed in a line at intervals of 4m e t e r s with first potato 24m e t r e s from the starting point. A constant is required to bring the potatoes back to the starting place one at a time. How far would he run in bringing back all the potatoes?

Two waves, each having a frequency of 100 Hz and a wavelength of 2.0 cm, are travelling in the same direction on a string. What is the phase difference between the waves (a) if the second wave was produced 0.015 s later than the first one at the same place, (b) if the two waves were produced at the same instant but the first one was produced a distance 4.0 cm behind the second one ? (c) If each of the waves has an amplitude of 2.0 mm, what would be the amplitudes of the resultant waves in part (a) and (b) ?

Two spherical , nonconducting and very tin shells of uniformly distributed positive charge Q and radius d are located a distance 10d from each other . A positive point charge q is placed inside one of the shells at a distance d//2 from the center, on the line connecting the centers of the two shells , as shown in the figure, What is the net force on the charge q ? .

Two cyclists,moving with equal speeds of 10 km/hr,are approaching each oher along a straight road.When the distance between them is 20 km a fly starting from cycle,keeps on flying alternatively from one cycle to the other.If the fly has a constant speed of 40 km/hr.Find the total distance travelled by the fly before the cyclists meet is.

25 trees are planted in a straight line 5 metre apart from each other. To water them the gardener must bring water for each tree separately from a well 10 metre from the first tree in line with the trees. Let d be the distance we have to cover in order to water all the trees beginning with the first if he starts from the well.Find sum of digits of d ?

Along a road lie an odd number of stones placed at intervals of 10 metres. These stones have to be assembled around the middle stone. A person can carry only one stone at a time. A man carried the job with one of the end stones by carrying them in succession. In carrying all the stones he covered a distance of 3 km. Find the number of stones.

Along a road lie an odd number of stones placed at intervals of 10 metres. These stones have to be assembled around the middle stone. A person can carry only one stone at a time. A man carried the job with one of the end stones by carrying them in succession. In carrying all the stones he covered a distance of 3 km. Find the number of stones.