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

The focal lenghts of objectives and eyepiece of a telescope are 200cm and 10 cm respectively. Is is used to get an image of the Sun on a screen placed 40cm behind the eyepiece. The diameter of the image is 6cm. What is the diameter of the Sun? Give the distance from earth to the Sun is 1.5xx10^(11)m .

the distance between two vertical poles is 100m and the height of one of them is double the other. The angle of elevation of their tops at the middle point of the line joining their feet are complimentary. Find the height.

The masses of two bodies are same. One is placed at the height of 10 m and the other is placed at the height of 20 m. Which one has more potential energy?

Find the force between two straight parallel wires, each of length one metre and cach carrying a current of 100 amperes when separated by a distance of one metre (given mu_0 = 4pi x 10^-7 N/m) .